O.S.S. - this World War II precurosr to the CIA could get a mention in the pages of G.I. Combat, I suppose, but I doubt it. Feel free to tell me I'm wrong!
THE OUTSIDER - a surprise inclusion in the original Flashpoint series was an updated version of this little-known villainous alter-ego of Alfred Pennyworth, Batman's butler. As far as I know, though, there's been no hint of him making an appearance in the New 52.
THE OUTSIDERS - Batman's weekend team, neither sight nor sound has been seen or heard of these guys since the relaunch / reboot and it seems unlikely that they'll be putting in an appearance any time soon. And good lord, how tiny is Halo's waist?!
OUTSIDERS HQ - and if the team aren't appearing, they won't be needing this, either.
PAKRAT - one of Atari Force. So no.
PARADISE ISLAND - despite being carried off by the gods in Infinite Crisis, I'm pretty sure it made its way back at some point after that. Either way, it's definitely in the New 52 but, as it's a location not a character, I'm not counting it.
THE PARASITE - as far as I know this Superman villain has yet to appear following the relaunch. It wouldn't surprise me if he shows up at some point, but I don't think it'll be before the end of the year.
PATCHWORK MAN - with the promised return of Anton Arcane in the pages of Swamp Thing (this is being written at the start of April, folks) I can see his brother showing up at some point as well. Before the end of the year? Possible but not certain.
THE PEACEMAKER - last seen (I think) as a tattooed mentor for Jaime Reyes's Blue Beetle pre-Flashpoint, I doubt we'll get to see him soon.
PER DEGATON - despite showing up as one of the time travelling bad guys in both Booster Gold and Time Masters (both written by Dan Jurgens) the storyline he was connected with seemed to peter out and go nowhere. He may show up on Earth-2 at some point but I doubt it right now.
THE PERSUADER - one of the Legion's villains, I don't know if there's any plans to bring him back right now. Dave Sopko, the official COEP Legion go to guy, says "I'd say there is a decent chance to see him again by years end...but you never know."
So in summary one in place (The Penguin) no definite predictions and one possible (Patchwork Man)