Batman / Superman: World's Finest

Gorilla Grodd

Flash villain

Bizarro

imperfect duplicate of Superman

Mercury

from The Metal Men

Robotman

Cliff Steele, of the Doom Patrol

Platinum

from The Metal Men

Negative Man

Larry Trainor

Ace the Bat-Hound

from Batman

Mr. Mxyzptlk

Superman villain, Silver Age / Modern Age

Eclipso

DC, vengeance demon

Lead

from The Metal Men

Gold

from The Metal Men

Iron

from The Metal Men

Tin

from The Metal Men

Will Magnus

creator of the Metal Men

Elasti-Girl

Rita Farr

Amazo

android, Justice League villain

Bat-Mite

Magog

David Reid

Doctor Destiny

John Dee

Condiment King

from Batman

Boy Thunder

David Sikela