The songs in Abby's lab. Are they Pauley Perrette's work, or random bands? And where can I get some of the songs?

They are random bands... the second cd in NCIS Soundtrack Volume 1 is Abby's lab music.

Most of the music on the second disc of the NCIS soundtrack is actually very different than the music we hear in the show. Collide is one of the few bands you can find both in episodes and on the soundtrack