Darrell Kunitomi is Lab Technician in The Non-Fat Yogurt (Season 5 Episode 7).
Daryl Keith Roach is Blind Violinist in The Subway (Season 3 - Episode 13).
David Blackwood appears in seven Seinfeld episodes. The first: The Robbery (Season 1 - Episode 3).
David Brisbin is Hand Model Client in The Puffy Shirt (Season 5 Episode 2).
David Byrd is Roger Hoffman, the pharmacist in The Sponge (Season 7 Episode 9) and in The Finale (Season 8 Episodes 23-24).
David Dunard is Security Guard in The Parking Garage (Season 3 Episode 6) and Rage-aholics leader in The Apology (Season 9 Episode 9).
David Mandel is Frolf Player in The Summer of George (Season 8 Episode 22).