I just looked and I can't find it either, actually :P Something to add to my to-do list!
But for now, here's a list of all the Quirks that are unlockable right now, to the best of my memory, and how to unlock them:
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Chloe > Original, Bimbo
-- Both are unlocked during the ORGANISATION storyline
Gwen > Damaged
-- Do not do naughty things with Gwen until you get a certain nighttime scene...
Jessica > Auntie, Adultress
-- "Auntie" = choose to call her "Aunt Jessica" at a certain point in her storyline
-- "Adultress" = choose to have sex with her in front of Tom at a certain point in the ORGANISATION storyline
Pixie > Cocksleeve, Schooled
-- "Cocksleeve" = at a certain point in Pixie's storyline you can make her big. When the power starts failing, let it.
-- "Schooled" = buy the college, then teach a class of Fey characters
Qarinah > Dreamgirl
-- "Dreamgirl" = Get Qarinah to level 4 love, then have the dream where the Beast comes for you
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Hope that helps! :)