A lot of what I listen to is non-RIAA, stuff from:
Nuclear Blast
Century Media
Razorback Records
Earache
Relapse
That makes up a good chunk of my collection.
The only real 'metal' label I can think of that is RIAA affiliated is Metal Blade. And Roadrunner.... if you can even call them a metal label anymore.
Either way, the majority of my music collection is from record labels that don't exist anymore, and lots of the albums have been out of print for two decades or more. How else am I supposed to get it??