Scenarios

Absolute Favorites:

Girlfriend x Boyfriend
Girlfriend x Girlfriend
Best Friend x Best Friend's Boyfriend/Girlfriend
Strangers
Neighbors
Roommates

Others:

Teacher x Student
Student x Student
Most Taboo relationships
Daughter x Father's Boss
Daughter x Father's Friend
Sister x Brother's Friend
Bad Girl x Good Girl
Good Girl x Bad Boy
Mafia Daughter x Opposing Mafia Daughter/Son


Those are the ones I can think of at the top of my head but I'm willing to do others!