Countries:
Irish, Scottish, English / British (Cockney, Proper and Liverpool), French, German, Russian, Canadian, Indian, Australian, Jamaican, Mexican (man and woman), Japanese
States:
Texas (several male varieties and a Texas female), South Carolina, Georgia, Illinois (specifically Chicago), Maine, California (surfer dude), Massachusetts, Minnesota, New York (mafia, Brooklyn, Jewish)
Characters / Impressions:
Christopher Walken, Woody Allen, Stewie Griffin, Herbert the Pervert, Sean Connery, Arnold Schwarzenegger, Joe Pesci, Ronald Reagan, Hannibal Lector, John F. Kennedy, Baseball announcer, Yoda, Mickey Mouse, Donald Duck, Old Jewish Woman, Jackie Mason, Gollum, Jar Jar Binks, Ozzy Osbourn, Walter Cronkite, Movie Trailer Guy, Sports Announcer, Gomer Pyle, James Lipton, Clint Eastwood, Jack Nicholson, Kermit, Miss Piggy, Ernie (of Bert and Ernie), Louis Armstrong, Robin Leech, fabulous life of guy, Valley Girl, Pirate, William Shatner, Timon/Pumba, Ted Koppel, Howard Cosell, Don Pardo, Bobcat Goldwaithe, Barack Obama
And MANY many more!