I have spent a lot of time thinking about My Little Pony, to put it lightly. Fanfic writing, brainstorming, etcetera. A lot of ideas come up that I can't necessarily work in at the time, or aren't important enough to make it into a story, things like that. So let's make a list, shall we? To note, some of these ideas are old, some of them are pretty new. Some I'll ignore if I've got this really good idea for a fic that contradicts a single point of headcanon. Here we go:
- Each of the mane six have a different sexuality, or at least fall on a different point of the Kinsey scale.
Only Rarity is completely straight, and she finds assumptions made about her because of her profession and love of beautiful things. Applejack strongly prefers males from a physical standpoint, but can form largely intellectual bonds with other mares, falling into a caretaker role with the likes of Fluttershy and Rainbow Dash. Pinkie Pie has a light preference for colts, generally knowing how to behave around them if she wants something and finding her instincts falling in place, but is open minded and has experimented since coming to Ponyville. Twilight I consider either evenly bisexual, or perhaps even pansexual; due to her strong magical talent, she has a very receptive soul. It was why she was able to form fast friendships with wildly different ponies as well; Twilight actually operates on a slightly different level than most ponies, simply incredibly in tune with magical auras the likes of which all ponies give off, and physical aspects of a relationship more or less fall in place once she's bonded emotionally with somepony. Fluttershy is close to asexual, having no drive from a physical standpoint, and issues with contact. However, her strong empathetic nature means that ponies often misread her intentions, and she has developed strong bonds with several friends that from an outsider's viewpoint are only barely platonic. Rainbow Dash is, well, gay. It's mostly a power dynamic thing; usually other mares either let her be the dominant one in the relationship, though what she really seeks is an evenness without competition, where she can flip between being the dominant one or letting the other take over for a while, as the situation calls for it.
- Rainbow Dash was orphaned
Dash's mother was unable to care for her, young, single, and with barely enough money to feed herself, so gave Dash up. She was adopted while young by Fluttershy's family, and the two are legally sisters. She knows her past and has since young, given how very different she is from the rest of her family. She and Fluttershy tend not to spell out their relationship because Dash has difficulty admitting she was unwanted. She's never met either biological parent, but has claimed that if she ever meets her mother she'll greet her hind-hooves first. She's had a personal crisis over Fluttershy in the past, trying to reconcile her unconditional love for the pegasus with their relationship as sisters; things have recently become clearer to her, and she understands better that her love of Fluttershy is not romantic.
- Twilight Sparkle is the (distant) descendant of Celestia
The Sparkle line are all, actually, direct descendants of the princess. It began with a royal indiscretion several hundred years ago, but Celestia has always watched out over her line, trying not to favor them but keep them from any great harm all the same. She has never once revealed her link to the mortal ponies, and it has never been an issue. She intervened with Twilight only because she had no choice; that was why she already knew the filly's name. Related to that:
- Twilight's extended family are prominent in higher circles, but not her immediate family
The Sparkle name is several hundred years old, and has always enjoyed good fortune. They have produced a multitude of mages, scholars, scientists, guards, and so on. Twilight's mother was openly scorned for her choice of husband, and cut ties with the rest of the family. Twilight has met her mother's family only twice, her father's family much more often. Her mother's mother in particular has experienced numerous frustrations that Twilight has encountered such royal favor, given that Twilight's mother's rejection was meant to be a temporary punishment designed to teach her a lesson. They have never reconciled.
- Celestia regrets what she did to Twilight
You heard me, what she did to Twilight. She trained the filly in precisely the right sciences and magics to survive an extended confrontation with Nightmare Moon, even subliminally planting the technique of "blinking" (teleporting) into Twilight when she couldn't manage to teach it through traditional methods (it's not meant to be a spell normal ponies can learn; it's an inherent ability that points to Twilight's royal blood). She never intended Twilight to defeat Nightmare Moon, just distract her until sunrise, when Celestia herself would step in. In the worst case scenario, a sealed envelope was to be opened by her most trusted advisor naming Twilight as successor to the throne; she is actually far more direct a descendent than Blueblood, whose claim is dubious and undisputed because no one cares. It was only after Twilight unlocked the power of friendship, and showed clear preference to her day-old friends to her life in Canterlot, that Celestia realized how badly she had used the pony. She purposefully distances herself these days in order to give Twilight a more normal life; secretly, she is nearly heart-broken every time Twilight bows instead of rushes up to her in affection like she used to
- The Nightmare loved Luna
The nightmare that possessed Luna was born of her own jealousy and desires. It never treated Luna as an enemy, and in fact its entire personality was based on the conviction that Luna had to be mistreated and deserved more. It protected her, it did what she couldn't. If it did evil deeds then that meant Luna's hooves remained clean. During their banishment, the nightmare kept Luna asleep, so she wouldn't remember a thousand years of emptiness. After returning to Equestria, the nightmare saw a way out. It never meant to stop the mane six, only test them to make sure it was worthy, and purposefully sacrificed itself so Luna would have a second chance at her sister's side. It died so Luna might live, and it loved her.
- Rarity considers Spike like a nephew
Rarity's well aware of Spike's crush on her, but she also knows that the poor boy's young, lovestruck, and a little confused. She can't break it to him that she needs a pony, not a dragon, but neither does she realize how badly she's leading him on. This is because she does dote on him, thinking him the "perfect little gentlemen". She acts almost like an aunt to him, encouraging him, telling him how adorable he is, and so on. Secretly, it worries her how easily she fits into a semi-maternal role, as she worries it's a sign she's losing her youth. As a side note, this is why she seems increasingly desperate to find somepony to be with, before she finds herself an old spinster.
- Fluttershy resents Twilight
Twilight bosses her around, trivializes her concerns, and generally makes her life more frightening. Had she run into the unicorn during her assertive phase, she probably would have destroyed Twilight. As it is, friction is building, and left unchecked might break apart the elements. Dash has been watching out for Fluttershy though, and is aware some kind of issue exists. There will likely be a confrontation in the near future
- Applejack only recently became aware of her sexuality
Applejack's answer to all questions involving dating has always been "haven't got the time for it". She's considered it a waste of time, and most of her notions of romance have had negative connotations; her parents were an arranged marriage, and so fed up with each other by the time Applebloom was born they had to coordinate who was going to be at the farm at which days to avoid running into each other, eventually finding it easier to never come back, even for their children. She has been flirted with by stallions, typically at rodeos, and on good days will even flirt back a little. She's never even been kissed. Recently, she's had to reconsider things; Fluttershy treats her in a way few others have, and is borderline suggestive, though Applejack knows she can be like that with other ponies. However it still appeals to her... but so does running alongside Dash, the wind in her mane and not a care in the world. She is unsure whether to pursue either mare.
- Twilight reads trashy romance novels
An insatiable lover of books, she spied some underneath her mentor's bed one day when Celestia left her alone there during studies. Thinking only to organize what the maids had 'obviously' forgotten to take care of, Twilight read an entire chapter before hearing Celestia return and hiding the book. Initially weirded out, Twilight returned to them again while a little older, going to great pains to not check them out of the royal library, to the point that she has technically stolen them (and returned them on time, of course). She has managed to accumulate a small (trunk's worth) personal collection that she hides so fiercely not even Spike knows they exist. She has tried her hoof at writing, but is aware all her characters are slightly-tweaked versions of her friends, and destroys most of her own writing. She has shipped herself with multiple ponies at that, more often than not coming back to herself and Song Smile, who is definitely *not* Pinkie Pie
- Pinkie Pie's childhood.... was pretty okay!
After Pinkie Pie's talent came to light, her parents knew she couldn't stay on the rock farm her whole life. They sent her to live with her grandmother, who lived in Ponyville. She visited the farm, and they visited her, quite often. Granny Pie did die of old age while Pinkie was still a teenager, but rather than move back to Ponyville Pinkie found work with the Cakes. She goes back to see her family regularly; Mother's Day, Father's Day, often for New Year's, and Sister's Day (a holiday of her own invention). Blinkie Pie is married and her family is set to inherit the farm, their parents "retired" but still working the farm. Inkie is more obviously unhappy, and Pinkie always tries to get her to come backto Ponyville with her. She has yet to succeed, but won't ever stop trying to bring a smile to her sister's face.
- The Elements of Harmony are sentient
Each element is a force, not of nature, but of ponykind. They are the accumulated spirits of all past ponies, and pony afterlife is a buddhist-like ascension to a collective consciousness that guides all living ponies and weave the threads of fate. Element bearers retain some level of independence in the afterlife, and often impart their wisdom and skill on the living bearers. Twilight has it hardest because her element has few guiding spirits.
- The element bearers are mixed up
Each of the elements can be split two ways. One, into the elements of Earth, Sky, and Heaven, which compose all living things. Two, into the forces of Light and Dark, that counterbalance themselves and represent the inert and the dynamic, the body and the mind, life and death. The problem is, kindness is an earthen element, and laughter is a sky element. Their true potential will never be unlocked because they are fighting the nature of their bearers, and are unbalanced. This is why both Pinkie Pie and Fluttershy have talents or abilities unusual for their species; the elements tried to make Fluttershy as earth-like as possible, and Pinkie Pie more pegasus-like. Some of this imbalance has already bled into their lives in more noticeable ways; Pinkie Pie's body overcompensated from being forced into this Sky-role and she thus has an extremely powerful connection to the earth, manifesting itself as a connection to the deep ley-lines of the earth, giving her access to unheard of magic-like abilities. Fluttershy meanwhile is left with a feeling of unworthiness and a weight on her spirit that literally and figuratively drags her down.
- Fate has provided each element bearer with a backup
None of them know it, either. The elements control much behind the scenes, but are not all-powerful, and their sentience has limitations. With forces of chaos in the equation, rather than pin everything on six unprepared mortals, an alternate candidate to each element has been groomed by the machinations of the elements themselves. Unfortunately, left to their own devices since the mane six are working out, these alternate six are beginning to discover their suppressed potential. It has the potential to wreak great havoc on harmony on Equestria, especially if the others discover their fate, and is proof the elements are fallible
- Celestia and Luna were once mortal
Celestia was trained as a pegasus knight in an old pony society, and Luna was a mage. They bore no relationship to each other. When ponykind rose up against Discord, both ponies led armies, exemplars of their kind. They threw their lives at Discord in order to seal him in stone, using the elements of harmony to an extent even the mane six have not matched (yet). The energies involved destroyed their physical forms, but their spirits refused to leave the mortal world while there were still ponies to protect. The elements, and the faith of ponykind itself, restored them to life as alicorns. They claimed sisterhood since both were restored through the same agent, reborn with the same "parents". It is also a mark of their closeness. Because Discord had control of the sun and moon for so long, both had lost all natural rhythm; Celestia and Luna took control of them to restore order. One day, the sun and moon will be able to guide themselves again, and harmony will reign complete. Then, Celestia and Luna will rest.
- Vinyl Scratch has blue eyes
Yep
- Octavia's cutie mark proves her talent isn't the cello
Octavia has a love of composition, and only plays to pay for her pricey Canterlot home. At least, that was what she told herself six years ago. Her spirit has been steadily worn down by isolation, cynicism, failure, and contempt as an earth pony in Canterlot high society. She feels emotionally dead inside, and has forgotten her dreams. The rest of her quartet generally don't try to interact with her, as she's positively creepy at times. Really though, all she needs is something or somepony to wake her up from her living daze.
- Colgate understands time intrinsically
She can see its flow and to her each passing of a second is deliberate as a step forward. She could probably travel it freely if she could be bothered. Rather, this understanding has parlayed itself into an intense fatalism, as she can spy the "when", if not the "how" of everypony's death. The hourglass cutie mark represents her ability to mark deadlines, often with terrifying literalism. Berry Punch is one of her only friends because she both believes in Colgate's abilities, and isn't bothered by them. Colgate has told Berry when she was going to die; Berry responded by figuring another drink wasn't going to do her any harm then.
- Vinyl Scratch uses nicknames because she has to
Vinyl Scratch has an extremely hard time understanding and following spoken words, to the point it could well be an undiagnosed disability. She has to put things into song in order to remember them, her cutie mark representing the near incessant whistling she'd perform as a child once she learned this trick. Nicknames are easier for her to remember because they are less words to her and more pure thoughts, her interpretation of a pony's character (or as she calls it, "rhythm"). She plays her music loud to drown out the words that confuse her, and give her an excuse when she can't place some fact somepony told her earlier. A few names stick with her, however, like her mother's and her childhood friend, Octavia. It also led to her delinquency in the school system, as tests were impossible for her unless the teacher let her whistle, and she was never believed when she said she just couldn't learn what she was being taught. Had she received proper aid, her understanding of musical theory and incredible singing voice would have launched her to a career ten times what she currently enjoys.
- Spike's growth is stunted
Dragons really do only grow according to horde size. It was an evolutionary tactic so young ones would not have to compete with parents, and would remain below the radar until they were able to set up their own home. Normally dragons accumulate at such a slow rate their growth is mistaken as being linear with age, and once hordes are accumulated long enough the dragon's body "settles in" and won't revert even in case of lost horde. Spike will eventually grow in size as he inherits the library from Twilight at the end of her lifespan. His mental state, however, is slightly unhealthy, as he has lived for nearly two decades but his brain size is not correct for that amount of development.
- Derpy Hooves has Pinkie-like powers
Derpy's eyes can see things most ponies can't, such as a faint physical representation of a pony's magical aura. Also, they have a tendency to look at sources of incoming danger before they even become visible, allowing Derpy to know if a flower pot is about to fall or something. When she concentrates she can bring them together, but lets them roam because they can help her friends. The only caveat is her powers never help herself out. In fact, for every minor disaster she averts, one happens to her. Her being "accident prone" is actually a result off all the bad luck she stole from other ponies. She stopped Lyra from chipping a tooth on a "Baked Bad" and then tripped on a rake, making her nose bleed. She woke up Rainbow Dash when the mare was about to lose her job from being late too often, and her chair collapsed the next time she sat on it. Luckily, she has an extremely positive attitude, and even if nopony understands what she's doing she has friends who look out for her.
- Caramel is a pre-op transsexual
I don't know, I just think it's a cool idea. He's a bit of a mopey guy, and Big Mac has always looked out for him. He wants to repay that, knowing he's attracted to the stallion, but something holds him back. There's a wrongness about it, a wrongness that pervades many actions he takes. He wakes up feeling shame and doesn't know why. Rarity is the only pony who knows he has issues, and the two are secretly friends. He's afraid of being caught in the boutique when he already gets ridiculed about being Big Mac's "girl", things like that, but she makes him feel comfortable. And he just likes helping out with the dresses. Rarity has recently started purposefully leaving him alone in the back room, half-convinced he'd try one on if given the chance. She wants to use that experience to open a dialogue, convince him of the help he needs to seek in order to ever feel good about himself
- Rainbow Dash could get into the Wonderbolts, if she actually wanted to
Dash hasn't been to a Wonderbolt tryout in three years. She's afraid, because she knows she could make it. Heck, she could make it easily; she held back so she wouldn't discourage her trainees, but her wing-power already is well above the average for the Wonderbolts, and is just a hair's breadth away from Spitfire, who's a living legend. But each year she has a crisis of conscience and comes up with an excuse, just claiming to her friends she needed to perfect her routine instead. Truth is, she's terrified of leaving her friends, and it gets worse each year, especially now that Twilight has come around and made things interesting. The recent extension of the railroad to Ponyville would technically allow her to commute to Canterlot, daily if necessary, but she still isn't sure. Not even Fluttershy realizes Dash is doing this; recently though, some of her friends are finally beginning to wonder, and Dash knows she needs to make a decision.
- Carrot Top is a conspiracy theorist
The Carrot family are really big on the east end of Equestria, and Carrot Top struck out far away from their home turf to bring carrots to Ponyville. Having grown up where her family is all but revered, she is completely flabbergasted at how poorly carrots sell in Ponyville. In time, she came to blame the Apple family, who she now believes are actively sabotaging her and employing a fruit-based cartel to keep Ponyvillans in line and buying their produce. Over time, she's gone a wee bit nuts, possibly due to cutie mark failure insanity syndrome. Her theories range from the Apple family making deals with proprietors to lock her out (why else would the Cakes make apple-cupcakes but not a single carrot cake) to apple cider containing mind control chemicals (she's still trying to figure out how they added it in plain sight during the FlimFlamFiasco). She believes the elements of harmony are a cover story proving the Apple family have their hooks in royalty, and Nightmare Moon and the like were stunts to make Applejack (and her apples) into heroes.
- The role of cutie marks is evolving
For a long time, Equestrian society was very class based. It harkens back to the days of post-Discord rule, when everypony was required to do all they could to restore harmony. Pegasus ponies had to control the wild weather, only earth ponies could heal the land, and unicorns were left to oversee it all. Cutie marks were considered only helpful in maximizing efficiency, knowing who should plant the seeds as opposed to tend the weeds, and so on. The land is finally healing, and in fact the Everfree forest is a prime example of a more natural, chaos-free land, though it has sadly been twisted by poor national policies that drove undesirables (dragons, ursas, weeds like poison joke) into a concentrated area over generations. Psychologists debate on whether "Cutie Mark Failure Insanity Syndrome" even exists, or is simply a mix of misdiagnosed anxiety and underlying issues that are not being treated properly. Younger generations are rebelling against the status quo, taking cutie marks as indicators of interests, passions, and natural aptitude, often arguing they come far too young to meaningfully assign a pony's destiny. The mane six are unknowingly split on this issue, with Pinkie Pie, Rarity, and Rainbow Dash viewing cutie marks as open to interpretation, and Twilight, Fluttershy, and Applejack viewing them more literally and as self-descriptors.
- Spitfire is Dash's half-sister; neither are aware
Spitfire's father had an affair with Dash's mother, though she kept the resultant pregnancy from him. It was one of the reasons she gave up Dash rather than raise her, afraid of shaming the prominent Wonderbolt captain of the time. Dash strongly takes after her mother; it is possible that if her father ever saw her, he may recognize her. This is almost certain to happen sooner or later if Dash joins the Wonderbolts; her father is their coach, too old to fly at their speeds but far too good to just quit.
- Spike has a strong accent
Ponies are communicating as their vocal chords allow, through neighs and whinnies and the like, though their range is greater than ponies here on Earth. Spike of course can speak their language, but he sounds funny to ponies who have never heard him before. Gilda was the same way, and in fact was one of the few griffons to even bother with the pony language. The red dragon from "Dragonshy" knew enough of the pony language to get by, but many do not; when Spike spoke to those adolescent dragons, he slipped into his natural tongue without even noticing.
- Seaponies exist
Just not in Equestria. They're saltwater, and Equestria borders no seas. Their existence is mostly anecdotal, though Celestia and Luna have both encountered them. There is very little interaction between Seaponies and other races, mostly because the world of one doesn't concern the other. Even Discord mostly leaves them alone, finding them a lot less fun than other ponies.