May these great actors and actresses rest in peace: 

Neil Hamilton - Commissioner Gordon
Stafford Repp - chief O'Hara
Alan Napier - Alfred
George Sanders - Mr. Freeze
David Wayne - Mad Hatter
Victor Buono - King Tut
Micheal Rennie - Sandman
Vincent Price - Egghead
Liberace - Chandell
Carolyn Jones - Marsha Queen of Diamonds
Roger Carmel - Colonel Gumm
Tallulah Bankhead - Black Widow
Ethel Merman - Lola Lasagna
Art Carney - The Archer
Otto Preminger - Mr. Freeze #2
Maurice Evans - Puzzler
Rudy Vallee - Lord Marmaduke Ffogg
Bruce Lee - Kato
Walter Slezak - Clock King
Roddy McDowall - Bookworm
William Dozier - bit parts
Jay Sebring - Mr. Oceanbring from "The Bats Kow Tow"
Byron Keith-Mayor Linseed
Anne Baxter-Olga,-Zelda
Also Howie Horowitz, who appeared in cameo roles and was also the uncle of Lesley Gore.  And Myrna Fahey, who was a henchwoman to False Face; she had Technicolor hair long before it became popular in the 1980s. 

Burgess Meredith-Penguin

Ceaser Romero-Joker

Frank Gorshin-Riddler

Milton Berle-Louie The Lilac

Madge Blake - Aunt Harriet/Mrs Harriet Cooper