Good Omens: Crowley and Aziraphale. For notagain_again.
001. Post-cataclysm
002.Hurt/Comfort
003.Hate turns into love
004.Matchmaking (A and B are got together by their friends)
005.A and B are having a secret affair
006.A pretends to have (or really has) a fling with C in hopes of making B jealous
007.Last night on earth
008.A is a virgin; B shows him/her how it's done
009.Need to warm up
010.All of A and B's friends think they're already a couple
011.An overheard conversation gives A the wrong (or right!) impression about B's affections
012.A makes a bet with someone else that s/he can win B's affections
013.A walks in on B showering/undressing/masturbating/otherwise expecting privacy
014.A is running away from his/her friends
015. A gets stuck with a baby
016.Brought together by holiday
017.[Outside influence] made them do it
018.Amnesia
019.A becomes disabled in some way
020.Best friends