If you have no idea how to capitalize of the supplemental content without reading everything or if you have an interesting high concept you don't know how to map to game rules, ask me. I'll be more than happy to dig through the material to help you out. I need to learn this stuff anyway.
If you need inspiration for how to use some of the lesser known classes, look to archetypes to define some interesting roles.
All alternate racial/class traits and feats from any first-party material are fair game until I say otherwise.
Alignment is only relevant to me when it matters to the mechanics. In those instances, we can resolve alignment on the fly. Otherwise, I don't care. Alignment is too narrow and usually only serves as roleplaying frameworks which you guys don't need to make interesting characters.
Poisons are pretty broken. While the regular rules apply for injury-based poisons (e.g. applied to weapons and ammo), contact/ingested/inhaled poisons are subject to DM adjudication when used out of combat. (Hint: Awesome ways to poison people are more likely to work. Fortune favors the bold)