There are several Fandom lines I would like to get a PSL for, some of them are a bit cracky but I have always wanted to give them a shot.
Harry Potter Helga Hufflepuff/Tom Riddle- Be it a cross-gen scenario or one or both get misplaced in time. I would love to have a beauty and the beast sort of go at these two. I played Helga in a "Beyond the Veil" sort of situation once and she became rather close friends with Tom and I would love to take it a step further maybe have them both be rather young maybe 15 or 16 if he gets sent back in time.
Marlene McKinnon/Sirius Black - I had this pair a very long time ago and I loved it. My Marlene is hellishly Scottish and one hell of a rebel. I usually play her pureblooded with a DE father. The plot was Sirius and Marlene were betrothed when they were just babies and they aren't told till they are fifteen, so before he runs off to live with James. I always imagined they would be friends maybe even playful rivals if they both played quidditch.
Remus/Lily - I have played both of these two in a situation where they ended up together. They found a kinship with each other and by all canon accounts James is a jerk so yeah.
Rose P./Scorpius M. - I just think these two would be precious and I would be willing to play either.