TASVideos now supports 56 platforms/systems. Just finding games to TAS for some of them can be a challenge. There's no definitive criteria for what counts as obscure here, it's mainly just platforms that aren't on
Wiki: ListOfIdeas and don't have a wishlist thread. Just going to link game lists for now, finding good TAS options needs a deeper look.
32X:
40 games (6 are CD 32X)
BS-X (Satellaview):
231 games (116 listed)
Doom:
421 Megawads listed here. I'm not familiar enough with Doom to know where best to find level sets and if they're all TASable.
DSi:
117 DSiWare games
Jaguar:
50 games (
+more homebrew)
Jaguar CD:
11 games (+homebrew?)
macOS: Don't know where to start with this one. Needs to be a macOS game that can be ported to Linux.
64DD:
9 games. Most seem to be Mario Paint?
PC-98:
1228 games. No idea about compatibility with Neko Project II.
PC-FX:
62 games. Most of these are dating/visual novel games.
SGX:
6 games
SVI-3x8:
130ish games
TI-83: Various sites around. Is TI-83+ supported?
TIC-80: Some games
here and
here
Uzebox:
List
VBoy:
22 games
VEC:
28 games (+lots of homebrew)
Please feel free to suggest other qualifying platforms, resources to find games (speedrun.com is one), or specific games.