The number of episodes or episode sets that a Guest Star appeared as a villain. Anne Bancroft appeared as multiple villains. Catwoman, Riddler and Mr. Freeze were played by multiple actors. Shared episodes or episode sets were counted as a full appearance.
10 Burgess Meredith (The Penguin)
10 Cesar Romero (The Joker)
6 Julie Newmar (The Catwoman)
5 Frank Gorshin (The Riddler)
5 Victor Buono (King Tut)
3 Vincent Price (Egghead)
2 Anne Baxter (Olga)
2 Carolyn Jones (Marsha, Queen of Diamonds)
2 Cliff Robertson (Shame)
2 David Wayne (The Mad Hatter)
2 Eartha Kitt (Catwoman)
2 Milton Berle (Louie the Lilac)
1 Anne Baxter (Zelda)
1 Art Carney (The Archer)
1 Barbara Rush (Nora Clavicle)
1 Eli Wallach (Mr. Freeze)
1 George Sanders (Mr. Freeze)
1 Ida Lupino (Dr. Cassandra)
1 Joan Collins (The Siren)
1 John Astin (The Riddler)
1 Liberace (Chandell)
1 Malachi Throne (False-Face)
1 Maurice Evans (The Puzzler)
1 Otto Preminger (Mr. Freeze)
1 Roddy McDowall (The Bookworm)
1 Rudy Vallee (Lord Marmaduke Fogg)
1 Shelley Winters (Ma Parker)
1 Tallulah Bankhead (Black Widow)
1 Van Johnson (The Minstrel)
1 Van Williams (Green Hornet)
1 Walter Slezak (The Clock King)
1 Zsa Zsa Gabor (Minerva)