Well, might as well hop in. Haven't really used many canon characters in my posts though. [i]Might[/i] be missing a few, I'll comb through my posts later. This is what I can remember.

[hider=Punisher's (Tiny) NPC Index]
[b]Canon Characters:[/b]
Ben Urich (supporting character of some NYC heroes in Marvel canon; mentioned; field reporter for ABC7)
David Lieberman/Microchip (supporting character of the Punisher in Marvel canon; major supporting character; NYC cop working in cyber crimes, hacker, and mission control for Punisher)
Lawrence 'Squid' Loman (obscure Batman villain in DC canon; minor antagonist; NYC mobster, deceased)
Silvio Manfredi/Silvermane (Spider-Man villain in Marvel canon; major antagonist; NYC mob boss/businessman, deceased)

[b]Original Characters:[/b]
Anthony Gognitti, James Russo, Nicolas Francesco (minor antagonists; low level NYC mobsters, deceased)
Frank (Frankie) 'The Bat' Niagara (reference to Max Payne series; minor antagonist; high level NYC mobster/enforcer, deceased)

[b]Not Too Sure Yet:[/b]
An unnamed assassin ([i]possibly[/i] either Jigsaw or Barracuda, depending on if I want him to come back [if not, he's just a nameless OC]; minor antagonist; hitman)
[/hider]