Accents,
Slavic, russian, Polish, Ukrainian, etc.
Hispanic, Mexican, Cuban, etc.
Jamaican, Island, etc.
Various Southern styles, Texas, Georgia,, Virginia, Alabama, etc.
African-american, ghetto speech, but also a more affluent, educated, middle-class accent that still retains some African-American flavor.
Italian.
Indian.
British, Scottish, and Irish.
Australian and New Zealand.
Asian, Chinese, Korean, Vietnamese, Thai, etc.
Various African accents, Ghana, Zambia, etc.
Arabic accents, Middle Eastern cabdriver.
Impersonations.
Presidents: Reagan, Clinton, Obama.
Celebrities: Rush Limbaugh, Mark Levin, Cheech and Chong.
Singers: Neil Diamond, Neil Young, Elvis Costello, Graham Parker, Joe Jackson.
Good believable falsetto, female impersonation.