You can choose any Race from the Advanced Race Guide and the Psionics book. And you can play any non-evil Paizo Core Class, Base Class, Hybrid Class, Alternate Class, Psionic Class and those from Path of War.
Having an idea for a back up character can save time when giant spiders turn your main dude into a desiccated husk and put an egg sac in his skull.
Rappan Athuk for the win! Three times! Three TPKs so far.
We started at first level and made it to 7th level before being dispatched by a pair of iron golems and a ghost. The second time we started at 6th level and were all killed by a demon. The third time we started at 6th level and made it to 8th level before being killed by a room full of cultists, priests, a demon and a spectre.
Not sure when the next time we go again but I'm looking forward to it.