PPP and its remnants, now possibly aligned with Sharif
ISI, who have god only knows what agenda of their own
Islamic militants, who seem to overlap with ISI and probably have links to organised crime through Afghani heroin
Musharraf and a dwindling band of loyalists
The rest of the military, some of whom will be trying to replace Musharraf
The CIA doubtless also has some interest in what's happening.
Is that about right? Or is there more in the pot?
There are a few names to look for. One PPP leader is Aitzaz Ahsan, who was in solitary confinement recently (don't know if he still is) and told Bhutto not to cooperate with Musharraf, is quite popular, arguably more popular than the almost indisputably corrupt Bhutto. Implacalbe foe of Musharraf; if Washington is serious about democracy in PK rather than maintaining control via alternative conduits, he's a man to watch (but hint - don't hold your breath on Washington's desire for Democracy in PK).
This might also be a moment for Imran Khan to show he is not the political lightweight many accuse him of being.