Fantasy
Fantasy/SciFi themed Anime
NSFW
Not that any anime really is. These ones however are a bit more mature or outright adult content.
OP MC
Over Powered Main Characters
Romance, BL, GL, etc
Anime I consider Romance or Romantic. That can be straightforward or have plenty of other tags/genres mixed in. M+F, M+M, F+F all pairings included.
School
Anime that take place in or are themed around "School"
Video game vibes
Either takes place in a video game world, MC plays video games (enough that a good chunk of the setting is in the video game), or the world has a feel like that of a video game