so far two of spongebob's cousins have been shown in the series. one was Blackjack who appeared in the episode "Blackjack" and the second is Stanley S. Squarepants who appeared in the episode of the same name.
Black Jack
Mystery lol!
Mystery
Harold Squarepants
Jr.
Armor Abs.
The goo-la-goon
her name is Lowis SquarePants(:0 or mrs.SQUAREPANTS
His name is Larry the Lobster he is Spongebobs lifegaurd friend
Bob le Sponge.
Her name is Mrs. Puff and she is a blowfish.
Daniel Cousins's birth name is Daniel Lee Cousins.