I dont know if I ever talked about IAD worldbuilding with respect to mates but it's HILARIOUS so I have to now
Witches/sorceri - have no fated mates (on their end)
Elves - have no fated mate
Valkyrie - have no fated mate (on their end), can die of a broken heart though so that's fun
Lykae - recognize their mate by scent (both genders), are guided by the Instinct (psychic werewolf fortune telling), have hot full moon sex where there's biting
Vampires - heart stops upon adulthood (men) and will restart when they meet their mate. They then get a raging boner that can only be um... addressed by their mate and they kinda go insane if that doesn't happen (stop laughing)
Demons (most kinds) - male demons cannot ejaculate until the first time they're inside they're mate (stop laughing) which "breaks" the demon seal so they can... uh... uh...
And then humans are complaining...