I used to do the underground club scene in NYC back in the early 80s. Lots of bands that were unsigned, or on labels like Stiff. Also used to listen to NYU radio (WNYU) - "The New Afternoon Show", which showcased obscure artists, and dropped them like a hot potato if they got signed to a major label (it's still on the air, and AFAIK, still has the same playlist policy). Other fave obscure bands:
Robin Lane and the Chartbusters
Drill
Vixtrola
Fire Engines
VKTMS
Rip, Rig & Panic
The Higsons
Blotto
Richard Hell and the Voidoids
Lydia Lunch
Thee Headcoatees
The Reverend Horton Heat (I don't think this band is obscure, but nobody ever seems to have heard of it)
Sleater-Kinney
Spinanes
Frogpond
Curve
Looker
B Bang Cider
The Amps
Cats & Jammers
Rogers Sisters
Pee Shy
Pig Bag
The Histrioniks
Thermals
Failure
... and dozens more from the late 1970s to the present that I cannot recall right now. There is so much great music that I have yet to discover and hear!