Duplication (self) – The character can create duplicate bodies of themselves.
In Doctor Solar, Man of the Atom #12 (Gold Key), Doctor Solar shows he can make duplicates of himself when needed.
Duo Damsel (DC) can turn from one person into two (DC Who’s Who #7).
Image comics has Dupli-Kate (The Official Handbook of the Invincible Universe #1).
Duplicate Man (DC) makes a one shot appearance in World’s Finest V1 #106.
The Engineer (Wildstorm) makes duplicates of herself in Authority V1 #18 and then almost never uses this power again!
Jamie Madrox (Marvel) can turn into an army of duplicates (X-Factor V1 #146).
Multiplex (DC) can make identical copies of himself but also smaller copies of himself (DC Who’s Who #16).
Reprise (Dakotaverse) can make an unlimited number of duplicates of himself (Milestone Media Universe Card Set).
The Impossibles (Hanna-Barbera) included Multiman, who could make copies of himself.
Amber LeRoux (Wildstorm) – Gen13 V4 #26
Berbalang – D&D 4th Edition – Monster Manual 1
Ditto – Ben 10
Dr. Eisenstein – Unknown Worlds #22 (ACG)
Protean Scourge – D&D 3.5 – Monster Manual III
Squirrel Girl (Marvel) makes a duplicate of herself in The Unbeatable Squirrel Girl Beats up the Marvel Universe.
Copy-Cat can turn into multiple copies in the Venture Bros universe.