I guess it depends on what you mean by obscure. I've written for short videos where my work was the first and still only fic in the fandom, but they are available online, so not really obscure in that sense.

My most obscure gift (a Madness treat) was in the most obscure canon I've nominated and requested, RPF for a character from ancient Persia whose name is probably not familiar to anyone who hasn't specifically studied that era.