Studio drummer par excellence. Keltner is one of those guys who's played on hundreds of albums but nobody's ever heard of him.
Keltner played drums for The Traveling Wilburys as the unnamed "sixth Wilbury", and he also appeared in the "sorta-supergroup" Little Village along with John Hiatt, Nick Lowe, and Ry Cooder.
The list of people he's played backup for is a real Who's Who and much too long to list here, but just to give an idea of the breadth of his playing style, I'll list a few here: John Lennon, The Manhattan Transfer, Delbert McClinton, Van Dyke Parks, Arlo Guthrie, Mick Jagger, Randy Newman, Pink Floyd, Ravi Shankar, Fiona Apple, and Bill Frisell.