If Thoughts Could Kill is a module that contains a number of variant rules for psions. It presents a new psion table for base PPs and number of powers discovered that some feel is more appropriate for the psion power level. It also brings secondary disciplines into play, in which a psion can pick two other disciplines that can thereafter use the same stat as his primary for DCs and power selection. Many people complained that psions were too limited in power selection due to the reliance of each discipline on a seperate stat. It also has some new powers, feats and a prestige class, but those are the major variant rules.
I'll note that my preference with psionics would be for a psionics only campaign. Frankly, I feel the "Mulligan's Stew" feel of many campaigns works against them. Many settings just toss in everything and the kitchen sink and I think that dilutes the setting. Especially when introducing such major effects as entire fields of reality altering powers. A psionics only campaign would feel much "tighter" to me. I've also made a divine magic only campaign that I think works pretty well.
It's easy enough to introduce new powers into the psion's power list by simply modifying the spells found in the PHB. I'll note that If Thoughts Could Kill discusses this at some length and gives a large list of spells placed onto the psion power list, as examples.
I'll note that my preference with psionics would be for a psionics only campaign. Frankly, I feel the "Mulligan's Stew" feel of many campaigns works against them. Many settings just toss in everything and the kitchen sink and I think that dilutes the setting. Especially when introducing such major effects as entire fields of reality altering powers. A psionics only campaign would feel much "tighter" to me. I've also made a divine magic only campaign that I think works pretty well.
It's easy enough to introduce new powers into the psion's power list by simply modifying the spells found in the PHB. I'll note that If Thoughts Could Kill discusses this at some length and gives a large list of spells placed onto the psion power list, as examples.