Pretty much everyone on SNL.
Haven't there been some pretty vocal musicians?
Madonna
Bono
Cher
I think there were a lot who said they wouldn't perform at the White House if he asked them.
And then there were sports figures who refused to go to the white house.
oh, and Ashley Judd!
Everyone associated with the Marvel movies (Hulk, Scarlet Johanssen, Capt. America, and the director or producer)