My most prized is a glow in the dark White Zombie album signed by the entire band. I have a ton of WZ stuff signed by them.
I have picks, drumsticks and drum heads from Pantera, Slayer, Scatterbrain, Mucky Pup, Coroner, Anthrax, Green Jello (or Jelly) and more bands that I have forgotten.
I also have signed t-shirts from most of those bands.
I’ve met Pantera, White Zombie, Gwar, Christian Death, Pete Steele, and sat next to Marilyn Manson at a strip club. (he just played with a balloon the whole time)