Rich Little, never heard of him but he is very funny and good at impersonations.

[Greg]

Very funny Biden impression at 1min 30 seconds.

Rich Little.

This man is funny.  Very good impersonator.

[Mr. Mysterious]

Rich Little has been around for a long time. What really helped put him on the map were his impressions of Richard Nixon way back in the early 1970's. This was when the Watergate scandal was ubiquitous so he was very in demand on talk shows and game shows back then.