Dean Hallo is Steve Gendason in The Big Salad (Season 6 Episode 2).
Debra Jo Rupp is Katie, Jerry’s assistant in The Diplomat's Club (Season 6 Episode 22) and in The Abstinence (Season 8 Episode 9).
Debra Messing is Beth Lookner in The Wait Out (Season 7 Episode 21) and in The Yada Yada (Season 8 Episode 19).
Deck McKenzie appears in thirteen Seinfeld episodes. The first: The Revenge (Season 2 - Episode 7).
Denise Dowse appears in 2 episodes: 1) The Wallet (Season 4 Episode 5) and 2) The Couch (Season 6 Episode 5).
Diana Castle is Mrs. Zanfino in The Wait Out (Season 7 - Episode 21) and in The Foundation (Season 8 - Episode 1).
Dom Magwili is Dustin, the tallest of the towel guys in The Pool Guy (Season 7 - Episode 8).
Dublin James Wahlberg is Maurice in The Van Buren Boys (Season 8 - Episode 14).