I remember William “The Squire of Gothos” Campbell was a mercenary soldier in one episode. IIRC, his boss was plotting to take over the Southwest.
Leslie Parrish was on twice, once as a green skin Venusian.
“The Night of the Flying Pie Pan” I think it was.
Oh, you’re good.
I learn all this stuff while I’m alive so I’ll be really smart when I’m dead. 
No rush!
Partial list of Wild Wild West actors appearing on Star Trek (TOS):
Dick Cangey - Otto (Space Seed)
Bob Herron - J. Hunter stunt double
Michael Dunn - Dr. Loveless
Chuck O’Brien - Shatner stunt double
William Schallert
Robert Phillips - The Cage
Arthur Batanides - D’Amato
Walter Edmonton - Balok voice
Anthony Caruso - Oxmyx
Theodore Marcuse - Korob
Paul Comi - Stiles
Gregg Palmer - Spectre of the Gun
Morgan Farley - Archons/Omega Glory
Jon Lormer - Archons
Sebastian Tom - Shore Leave (Warrior)
Jack Perkins - Bread & Circuses
Alfred Ryder - Crater (Man Trap)
Jason Evers - Rael (Wink of an Eye)
Jeff Corey - Cloud Minders
Kathie Browne (Mrs. Darren McGavin) - Wink of an Eye
Harry Townes - Archons
John Hoyt - Dr. Boyce
Maggie Thrett - Ruth (Mudd’s Women)
Sherry Jackson - Andrea
Paul Fix - Dr. Piper
Perry Lopez - Rodriguez (Shore Leave)
Joseph Ruskin - Galt
Leslie Parrish - Carolyn
Vince Howard - Crewman (Man Trap)
Marj Dusay - Spock’s Brain
Byron Morrow - Amok Time
Bill Zuckert - Specter of the Gun
Elisha Cook - Cogley
Judi Shervan - Wolf in the Fold
Chuck Courtney - Patterns of Force
Billy Curtis - Journey to Babel
(Either I recognized the face, the voice or the name in the credits)
Many more to come.
Andrew “Garak” Robinson opposite Walter Matthau in 1973’s Charley Varrick.
Ken “Mr Vanderbilt” Lynch as “Det Sgt Durgo” in Anatomy of a Murder.
Nitpick: Vanderberg | Memory Alpha | Fandom
Great list, burpo!
Also seen recently:
Sam Anderson as a Fonzie-loving ob/gyn on the Friends episode where Phoebe has her babies
David Paymer as a nebbishy White House pollster in The American President
And in the same movie, Anne Haney as the President’s personal secretary
Wild Wild West list continued:
Walter Soo Hoo - Crewman (Man Trap)
Phil Adams - Klingon/stunts/Shatner stunt double
George Samaya - Errand of Mercy
Shari Nims - Sayana/The Apple
Denver Mattson - Stunts/Little Girls Made of?
Louie Elias - Crazed Crewman/Tholian Web
Carol Daniels - Zora/Savage Curtain
Roy N. Sickner - villager/Private Little War
Walter Bacon - Onlooker/City on the Edge of Forever
Al Wyatt Sr./Anti-matter Lazarus
George American Horse - Indian/Paradise Syndrome
Sam Bagley - Survivor/The Cage
Vincent St. Cyr - Father of drowning boy/Paradise Syndrome
Lincoln Demean - Sergeant/Assignment: Earth
Ed Peck - Col. Fellini/Tom’w is Y’day
William Windom - Commodore Decker
Ricardo Montalban - Khan
John Astin - Capt. J Daley (voice)/ Conscience of the King
Madlyn Rhue - Space Seed
Mark Lenard - Sarek
BarBara Luna - Mirror, Mirror
Antoinette Bower - Sylvia/Catspaw
Yvonne Craig - Marta/Whom Gods Destroy
Percy Rodrigues - Portmaster Stone/Court Martial
Susan Oliver - Vina/The Cage
Arlene Martel - T’Pring
Malachi Throne - Commodore Mendez/The Menagerie
William Campbell - Trelane
William Marshall - Dr. Daystrom
James Gregory - Dr. Adams/Dagger of the Mind
Bart La Rue - Yarnek/Savage Curtain
Reggie Nalder - Andorian/Journey to Babel
Vic Perrin - Nomad (voice)
Maybe more later.
Hoo doggies! Thanks again, burpo.
Ashley Judd plays herself in the very good recent movie about the NYT breaking the Harvey Weinstein story, She Said.
Ian “Old Guy” Wolfe as murder victim “Mr Miller” in Hawaii Five-O’s “Retire to Sunny Hawaii—Forever.” (1975)
Susan “Mara” Howard and James “Dr Adams” Gregory in Columbo’s “The Most Crucial Game.”
Of course, only one person ever portrayed himself in Star Trek.
Ray “Groundskeeper” Walston as “Joe Dobisch” in 1960’s The Apartment.
Actor Nick Dmitri played various bit characters in various ST incarnations, all uncredited, as were most of his motion picture roles.
He is probably best known, if at all, as the ‘champ’ that Charles Bronson goes up against in the movie “Hard Times” (1975)–not to be confused with bald brute Robert Tessier, the opponent who is probably better remembered from that movie.
Anyway, In a “Monkees” rerun, he played a Clark Kent/Superman character in one episode, and in another, he was a stagehand on the “Captain Crocodile” show, both uncredited.
Another from Wild Wild West – Sarah Marshall; Janet Wallace/Deadly Years
Still another from WWW – Sandra Smith; Janice Lester