One of my story ideas I've had for a long time has the person who initially appears to be the villain turn out to be the love interest, and one of the people who is admired and has a reputation as an important good guy at the start turns out to be such a villain that the otherwise-pacifistic MC has to decide to kill him for everyone's protection.

Currently I've also been playing with the idea for a cowritten project where I would create a team of anti-villains and my partner would create a team of anti-heroes or possibly regular heroes, and we would fight them against each other, sort of like a roleplay except we would each control a team rather than a single character. I lack the co-writer though, so that project is on hold unless/until I find one.