The List of Superhuman Characters who Can Split into multiple versions of themselves or multiple physical people

[Randy Jackson]

Here's the list of Superhuman Characters who can create multiple duplicates of themselves or separate into separate beings:

The list so far:

Captain Everything (normalman) 

Composite Superman 

The Collective Man

Doctor Manhattan 

Doctor Strange

Duo Damsel/Triplicate Girl

Eclipso

Flashback (Omega Flight) 
Jamie Madrox

Multi-Man (the Impossibles) 

Multiplex

Multi-Woman (Top Ten) 
Negative Man (Larry Trainor)

The Seven Deadly Brothers 

The Silent Majority

The Spectre

Swamp Thing

The Troll
Twice (My Hero Academia) 

[Dave Palmer]

Multi Man of the Impossibles

[Randy Jackson]

Added

Dave Palmer said:

Multi Man of the Impossibles

[Jeff of Earth-J]

Flashback of Omega Flight.

Flashback could create "duplicates" of himself by summoning other versions of himself from the near future. One of his future selves was killed in battle in Alpha Flight #28, which meant he was going to suddenly die sometime soon, but he had no idea when it would be. 

[The Baron]

Multi-Woman from "Top 10"

[The Baron]

Marvel's Collective Man

The Baron said:

Multi-Woman from "Top 10"

[The Baron]

DC's Seven Deadly Brothers

The Baron said:

Marvel's Collective Man

The Baron said:

Multi-Woman from "Top 10"

[Randy Jackson]

Thanks for this. I remembered that scene but couldn't place the character name. 

I've added all other suggestions 

Jeff of Earth-J said:

Flashback of Omega Flight.

Flashback could create "duplicates" of himself by summoning other versions of himself from the near future. One of his future selves was killed in battle in Alpha Flight #28, which meant he was going to suddenly die sometime soon, but he had no idea when it would be. 

[The Baron]

The Silent Majority

[Randy Jackson]

Added. 

The Baron said:

The Silent Majority

[Philip Portelli]

As Firestorm had the power of fusion, his enemy Multiplex had the power of fission!