There are actresses in the Seinfeld episodes which have appeared more than once as different characters. I can think of at least two of them:
1. "This Blonde Actress - name unknown" - this person played Poppy's daughter (?) and refused to take a bite of Jerry's apple pie; and she also was in the limo of the Aryan/Nazi leader going to Madison Square Garden.
2. "This Brunette Actress - again name unknown" - this person played some southern belle with relations with George and then Jerry, who left erogenous answering machine messages; she also was the waitress at Monks who did not enjoy George's spin on manure.
Any opinions besides my insanity? (grin)