I have had enough. I am putting this subject to rest.
I have gone through all my Seinfeld tapes of all the episodes I have (not all since they all haven't been shown in Australia) and have come up with all the blondes that are focused within Seinfeld.
Jerry:
Laura (The Lipreader): the deaf lineswoman.
Tia (The Airport & The Pick): the model for "Ocean" by Calvin Klein.
Donna Chang (The Chinese Woman): the "chinese" woman from Long Island.
Cathy McTierny (The Beard): the policewoman who didn't believe Jerry hadn't seen "Melrose Place".
Shelly (The Doodle): eats pecans and leaves them on Jerry's plate.
Bridgette (The Diplomats Club): the model at the end of the episode.
Gennica (The Understudy): the understudy to Bette Midler whocries about anything that happens to her.
Naomi (The Watch & The Bubble Boy): the girl with the bad laugh ("sounds like Elmer Fudd sitting on a juicer").
Sandra (The Cheever Letters): assistant of Elaine who talks dirty.
Gail (The Shoes): ex-girlfriend who doesn't kiss goodnight.
Tawni (The Conversion): the girl with the fungicide.
Karen (The Chaperone): Miss Rhode Island.
Holly (The Wink): Elaine's cousin who persists with giving Jerry meat.
Shelia (The Soup Nazi): a.k.a Shmoopie.
Lena (The Sponge): too good to be bad, storage of Today Sponges.
George:
Susan: the fiance.
Gwen (The Lipreader): drops him because of icecream on his face.
Bonnie (The Label Maker): has male roommate and wants menage-a-twar.
Noel (The Pez Dispenser): the piano player.
Alison (The Outing & The Smelly Car): wants to kill herself because George is dropping her. Attracted to Susan.
Victoria (The Opposite): likes "Opposite" George.
Kramer:
Lola (The Handicap Spot): the handicapped woman.
Olive (The Pie): the woman with long fingernails.
Hildy (The Soup): waitress from Reggie's.
Marion (The Library): the librarian.
Becky Galke (The Good Samaritan): "you are so good looking".
Mona (The Smelly Car): Susan's lesbian girlfriend.
Other Blondes with speaking roles:
Angry Woman (The Handicap Spot): angry about the car in the handicap spot.
Corinne (The Limo): woman who got hit in the head with Elaine's organiser.
Jerry's Mother - Helen
George's Mother - Estelle (in early episodes, later episodes with red hair)
Kramer's Mother - Babs
Woman (The Doorman): complains about the sofa going missing.
Woman (The Marine Biologist): "there's a beached whale, she's dying"
Saleswoman (The Pie): sells George the suit that swishes.
Waitress (The Big Salad & The Pledge Drive): gives George "the finger".
Tammy (The Stand-In): the little person.
Woman (The Fire): talks about how Kramer saved Toby's pinky toe.
Noreen (The Pledge Drive & The Chinese Woman): goes out with hightalker and longtalker.
Angry Woman (The Secretary): wants to get into Kramer's dressing room.
Mrs Enright (The Gymnast): mother of Lindsay who catches George eating out of trash.
Woman (The Race): mother of child.
Mrs Stevenson (The Beard): wife of boss at ballet.
Debby (The Scuwflaw): woman who liked Gary "with" cancer.
Truck Driver (The Keys): takes Kramer to L.A.
Rental Car Agent (The Alternate Side): doesn't hold reservation of car.
Buxom Woman (The Doorman): claims George and her a twins because they are wearing the same shirt.
Murphy Brown (The Keys)
Bette Midler (The Understudy)
Cathy Lee (The Opposite)
Flight Attendant (The Diplomats Club): tells Jerry that the pilot doesn't want him on the plane.
Judy (The Doodle): Elaine's friend from Viking Press.
Rita (The Apartment): director of Madison Square Garden.
Ava (The Revenge): in George's office meeting.
Roxanne (The Apartment): marathon party host.
Aunt Stella (The Pen): Uncle Leo's wife.
Tall Woman (The Boyfriend Pt II): who gives George back his wallet.
Waitress (The Bubble Boy): doesn't give Jerry's picture back in the diner.
Eva (The Limo): the woman Nazi.
Cynthia (The Watch): in Russell Dalrymple's apartment.
Barbara (The Dinner Party): takes last chocolate babka.
Party Guest (The Baby Shower): asks when the baby is due.
Flight Attendant (The Baby Shower): tells Jerry the plane is flying into a blizzard.
Mrs Sweedler (The Bris): hospital adminstrator.
Woman (The Engagemant): with dog.
Elsa (The Puffy Shirt): woman who discovers George as a hand model.
Assistant (The Puffy Shirt): asks George out on a date.
Chelsea (The Trip Pt I): the woman who is killed.
Judy (The Hot Tub): the mother of the "bastard" child.
Other Blondes:
Ticket Collecter (The Airport)
Breastfeeder (The Stand-In)
Manager at health club (The Wife)
Woman at circus who helps put Misha's cape on (The Gymnast)
Aunt Phyllis (The Gymnast)
Mother feeding baby in Monk's (The Apartment)
Woman crying about Kramer's description of circumcision (The Bris)
That is about all of them. I didn't count the blondes standing about in the background because the cameras didn't focus in on them.
If there are any more blondes that I have missed, please add them to this list. (I now have RSI in my hands).