I am playing a Kineticist from the Occult Adventures Playtest, and am looking for a specific effect to help with the Burn class feature: the ability to take nonlethal damage up to my maximum HP, rather than current HP, before losing consciousness.
This feature is available to the Medium class, also in the Occult Adventures Playtest, through the Neutral Constitution spirit called "The Teamster". The Greater Spirit Power for this spirit is called "Knife's Edge", and is worded as follows:
Knife’s Edge (Greater, Su): Double your Constitution score before adding the Teamster’s spirit bonus to determine when hit point damage kills you. If you are not immune to nonlethal damage, when you are at 0 hit points or below, convert the first 5 points of damage you take from each attack to nonlethal damage. You are not knocked unconscious by nonlethal damage unless you have as many points of nonlethal damage as your maximum hit points, rather than your current hit points. (Emphasis Mine)
But, because the Greater Spirit Power is a 13th level Medium class feature, it would be a very long wait for multi-classing (Unless Variant MultiClassing somehow allows it to work) just for that benefit. This is why I'm looking for something that doesn't require a lot of investment in another class (Though I am fine with a heavy feat or gold investment.)