there are some bands that seem to consist of only one member. i am not referring to those bands who would be nothing without their singer/songwriter (f’rinstance bush and gavin rossadle, everclear and art alexaksis, to name a couple) but bands that genuinely consist of only one member.
nine inch nails - there aren’t any apart from trent reznor, are there?
eels - i still think they count. e is the eels, although butch consistently drums for them/him.
I believe Trent Reznor does have other musicians play instruments on his recordings. I’m not sure what percentage is Trent/others. But the lion’s share of the work is Trent’s AFAIK. He has a touring band, but I think he’s the only “official” member of NIN. I’m sure there is a rabid NIN fan who can elaborate on this.
Another artist in the same vein as Trent is Beck. He plays much/most of his own stuff, with some other musicians in places.
Also, Scott Weiland did most of the work on his solo album. Dave Grohl recorded the entire first Foo Fighters album on his own (and much of the drumming on subsequent albums), and Billy Corgan recorded most every bit of Siamese Dream on his own due to his perfectionist tendencies (though I think he did have someone else do some of the drumming).
IIRC, there’s a band, Vast, that consists entirely of one person, in that he writes all the music, and has others perform it…and the others are not necesarily the same song-to-song, or album-to-album. I could be wrong, though.
In a way, at least early on. But starting with Mellon Collie and the Infinite Sadness, the whole band actually was allowed to play their own instruments in the studio and collaborate on a little of the writing.