Oh man, finally the Advanced Player's Guide for Pathfinder came out and there are definitely some good news for poisoners here.
Alchemist:
Concentrate poison:Sticky poison:Summoner:
Poison (Ex):Rogue:
Lasting Poison (Ex): A rogue with this talent can apply poison to a weapon in such a way that it is effective for two successful attacks instead of one. The poison has a reduced effect, however, and saves made against the poison receive a +2 circumstance bonus. Applying poison in this way requires a full-round action, or a standard action if the rogue has the swift poison talent.
Master Poisoner (Ex):Sorcerer:To go along with Serpents Fang, here is the endcap ability for the Serpentine Bloodline:Feats:
Master AlchemistSpells:
Accelerate Poison - Probably my favorite
School transmutation; Level druid 2, ranger 2, sorcerer/wizard 2
Casting Time 1 standard action
Components V, S, M (a thorn)
Range touch
Target creature touched
Duration instantaneous
Saving Throw Fortitude negates; Spell Resistance yes
You hasten the onset of poison in the target. If the poison normally has an onset time, its effects begin immediately. If the poison has no onset time, its frequency is doubled, requiring two saving throws and inflicting damage twice per round or minute, though its duration is halved. Accelerate poison does not change the cure condition for the poison. If the target is affected by more than one poison, you may choose which is affected if you administered the poison; otherwise, randomly determine which poison is affected.
I'll mention the Transmute Potion to Poison spell here just to say that it's rubbish. That is all.