Nightride.FM has datawave (sort of 80s/early 90s computer-aesthetic synthwave) and horrorwave (darkwave subgenre, very 80s horror movie inspired) stations.

My favorite sub-genre is probably Cyberwave, but of the niche genres I've come across, I've gotta give props to Simpsonwave (which even has its own Know Your Meme page)

I love Mallsoft (https://en.wikipedia.org/wiki/Mallsoft) which is a subgenre of Vaporwave.

Sovietwave is one of the weirder ones I've come across, but it works