You can't go more obscure than me.
Even among my friends, I'm still well acquainted with a lot of old school games.
During the late 90s (at the start of the emulation scene) I was a junkie of downloading and collecting all the games I didn't play on my younger years with consoles and I basically ended up getting intimate with a lot games and some so obscure that pretty much no one who didn't dip its toes into other something that the mainstream wouldn't even know. As of late, I probably rolled my fingers at mostly all the NES/SNES/GB/MS/GENESIS catalogue I could get my hands on (not on existence, that would be too much) and played from the mainstream to the obscure.
I think I've done a bit of obscure girls now and in the past, but it is probably just the tip of the iceberg of what I could actually do!
This could be probably one of those examples. We all know Maki (FF is mainstream as it gets), but not
Rosa, which comes from a fairly obscure beat 'em up that most of my commenters didn't even knew it existed.