the one where you only see color once you meet your soulmate(s) (so you don’t know them until you see them), and it goes away when they die
the one where you don’t know your soulmate(s) until you touch them
the one where you don'y know your soulmate(s) until you hear them speak, or hear them speak a certain word; your name, for example
the one where you get the name of the person in their handwriting on your body somewhere at a certain age
the one where the first thing they say to you appears instead
the one where you get each others’ fingerprints
the one where you get matching marks/symbols/tattoos
the one where your marks or words that change depending on what’s going on with your soulmate(s)
the one with the clock that counts down the time until you meet your soulmate(s) (multiple clock for multiple soulmates? one click until you meet them both? unexpected third soulmate showing up after the clocks drop?)
the one where when you sleep you dream of whatever they’re experiencing from their point of view until you find them, or AFTER you find them
the one where you can straight up talk to them in dreams until/after you find them
the one where you form a telepathic/empathetic link until/after you find them
the one where you share extreme physical sensation until/after you find them; if one of you hurts the other one hurts, if one of you is getting lucky the other one gets a little hot and bothered
the one where the closer you are to them the more aware of them you become, and you find them playing a hot/cold game; for instance, colors get brighter and brighter the closer you are and fade into gray when they’re too far away
the one where once you turn a certain age/one night a year you swap bodies with them for one night and you have a limited amount of time to leave/collect clues to their identity
the one where being next to your soulmate(s) can heal you from things people don’t normally heal from
the one where only your soulmate(s) can kill you (maybe you can still be killed by age/disease, maybe not, maybe you become vulnerable only after you lose your soulmate(s))
the one where reincarnation is also a thing and meeting your soulmate(s) either unlocks or erases memories or your past lives until the next one
the one where in universes with magic meeting your soulmate(s) activates your powers/unlocks more powerful magic

SOULMATE AUS WITH COMPLICATIONS:

blind characters who can’t see if the world’s in color or black and white
characters like x-men’s rogue who literally can’t touch people; characters who have been through trauma who don’t want to touch people
hard of hearing characters like clint barton who can’t hear their soulmate speak without hearing aids/at all or on the flipside characters who can’t speak; maybe it still works in sign language, or maybe it doesn’t
people who can’t read/can’t read the language the words on their body are in
characters like bucky barnes who’ve lost hands and/or had their fingerprints removed
soulmate clocks that time out in the middle of the crowd; there’s an entire craigslist category for finding who else was there that day with a clock that timed out too
famous characters speaking to or performing for a crowd and suddenly their world is in color/their clock times out/etc and every member of the audience pretends to be this celebrity’s soulmate and a cinderella type situation ensues with the finding
soulmates playing the hot/cold game and they kEEP MISSING EACH OTHER
insomniacs who rarely sleep, much less at the same time/different time than their soulmates
soulmate ot3s/ot4s/otmores where you dream in varying people’s povs every time you sleep and get super confused
people who get sick or injured and frantically search for their soulmates so they can survive
people who need to be in medically induced comas and their soulmates have to stay away so they don’t accidentally wake them up
the one where soulbonding is actually a choice and someone chooses to bond with someone they may not know or like to save their lives and have to figure out if they can unbond or if they have to live with the situation (and of course learn to love one another either romantically or not)
new souls who don’t get memories of past lives because they don’t have one and panic
muggles/people without powers who of course CAN’T get them upgraded or unlocked

COMBINATION AUS:

the one where you one or both of you have to do all three (see your soulmate(s), touch your soulmate(s), hear your soulmate(s)), or all three have to happen at least once between the 2+ of you
or it’s completely random how you find your soulmate(s): one of you gets a name and the other gets a fingerprint, one of you has to hear your soulmate and one of you has to see them, etc; particularly useful if you happen to be blind or deaf
same for characters with other disabilities/who have “complications”: they get or find a different way of finding their soulmates, not better or worse, just different

THEN THERE’S SOULMATE AUS THAT DON’T HAVE TO CONFORM TO LIFELONG MONOGAMY:

the ones where you have more than one romantic soulmate at the same time or you get a new soulmate after the first dies
the ones where people have multiple soulmates of different types and it’s color coded; a red name/mark/etc for love, a blue one for friendship, etc; for the ones where you start seeing color you get a new one for each soulmate
the ones where some people have romantic soulmates and some don’t, and those that don’t are still perfectly happy anyway, maybe in a relationship anyway, maybe not
the ones where some people have multiple romantic soulmates who may or may not also be soulmates with each other
aromantic or asexual people who have soulmates who are not and they manage to work it out
romantic and sexual people who don’t have soulmates but find happiness anyway, either with someone like them or someone not like them

SOULMATE AUS THAT EXPLORE THE RAMIFICATIONS OF SOULMATES BEING A THING:

the ones where soulmates are for everyone and get legal aid to help stay together, like if their in-laws try to keep them apart/someone risks getting deported/someone gets drafted/whatever
the ones where soulmates are super super rare and TECHNICALLY get exempted from shitty things like “people of different races/the same sex/etc can’t get married/have relations/etc” but maybe still face a lot of prejudice and they fight to get those types of awful laws lifted for everyone
agencies that exist to help you find your soulmate(s) or figure out which soulmate thing you have but some of them are just shams, bonus points for this being in a verse where the thing is exceedingly rare to begin with
people pretending to be soulmates to take advantage of the laws, for good or ill; the couple who loves just as fiercely as a soulmates who will do anything to stay together, or the shitty people who try to claim they’re mated to people who’ve rejected them so they “have” to stay together
tabloid mags photoshopping matching soulmate marks or following big legal cases where someone tries to prove or disprove that they are soulmates with someone else
soulmates in universes where they’re a rarity or rare soulmate types like ot3s/ot4s/otmores in dodging government officials because they don’t want to become lab rats
people who don’t believe in soulmates until it happens to them, or people who believe hardcore and want to find theirs but they don’t necessarily have one, or don’t have a romantic one
little rituals that make finding your soulmate more likely, like shaking hands with people as often as possible even with the cashier ringing up your groceries, repeating each other’s names after you’re introduced, etc