1. Omegaverse. I consider this more to be a subgenre than a trope, but people were mentioning this just to shit on it on the other thread, lol. So I am going to mention this here as well.
Shamelessly plugging my favorite omegaverse here, Kouguu no Omega.
2. Slowburn romance. Not so slow that I become a grandma by the time the MCs hook up, but sl......