Just kinda curious...
Some options (I know theres a lot more):
Mel Brooks
Don Rickles
Rodney Dangerfield
Joan Rivers
Groucho Marx
George Burns
Any of the 3 Stooges
Milton Berle
Sacha Baron Cohen *yea, I know he's a Brit.
Gary Shandling
Jerry Seinfield
Lotsa good ones, but Don Rickles (RIP) is my favorite.