Sandman (William Baker, a.k.a. Flint Marko) Created by writer Stan Lee and artist Steve Ditko, Sandman first appeared in The Amazing Spider-Man #4 (Sept. 1963).
Mister Mxyzptlk Created by Jerry Siegel and Joe Shuster, and first appeared in Superman (Vol. 1) #30 (September 1944).
General Zod Created by Robert Bernstein and George Papp, General Zod first appeared in Adventure Comics #283 (April 1961).
Doomsday Created by writer-artist Dan Jurgens, Doomsday first appeared in Superman: The Man of Steel #17 (Nov 1992).
Bizarro (Bizarro Superman) Created by writer Otto Binder and artist George Papp, Bizarro first appeared in Superboy #68 (October 1958).
The Scarecrow (Dr. Jonathan Crane) Created by Bill Finger and Bob Kane, The Scarecrow first appeared in World's Finest Comics #3 (Fall 1941).
The Penguin (Oswald Chesterfield Cobblepot) Created by artist Bob Kane and writer Bill Finger, The Penguin first appeared in Detective Comics #58 (December 1941).
Mr. Freeze (Dr. Victor Fries) Created by Bob Kane, Mr. Freeze first appeared in Batman #121 (February 1959).
Bane Created by Chuck Dixon, Doug Moench and Graham Nolan, Bane first appeared in Batman: Vengeance of Bane #1 (January 1993).
Mystique (Raven Darkhölme) Created by artist David Cockrum and writer Chris Claremont, Mystique first appeared in Ms. Marvel #16.