This is yaoi:

Genre: Comedy, Drama, Romance, Yaoi.

Genre: Yaoi, Comedy, Romance, Slice of life.

This is shonen ai:

Genre: Comedy, Fantasy, Adventure.

Genre: Drama, Fantasy, Romance,Mystery, Shōnen-ai.

What’s the difference?

Yaoi is used to describe titles that primarily feature sexually explicit themes and sex scenes, while shōnen-ai is used to describe titles that focus primarily on romance and omit explicit sexual content, although sexual acts may be implied. 

This is fanservice:

These are animes with canon lgbt characters/couples but  don’t have romance:

Genre: Dark fantasy, Horror, Magical girl.

Genre: Post-apocalyptic, Mecha.

Genre: Science fiction, Dystopia.

Genre: Dark fantasy, Post-apocalyptic

Who knows: