A bunch of the Hammie's still use vacuum tubes in all their equipment. There should be quite a few miniature tubes and driver tubes there. I doubt we will see any single ended stuff but there should be plenty of 12 and 6 series tubes along with output tubes (el84, el34, 6l6) and the like. Who knows, you might even run across some beam tubes like 211's, 845's, or the 1000+ volt 833.
There should be plenty of tube testers and a miriad of other test equipment (VOM, sig gen, cap testers, scopes) there for sale too.