When Wizards of the Coast moved Dungeons and Dragons from version 3.5 to 4th Edition the licensing of 3rd edition 3rd party products went away. For Green Ronin, the solution they came up with was to rebrand those old products as '3rd Era' and re-release them as PDF documents. One of the first I've seen advertised was 'The Psychic's Handbook', an alternate set of Psionics Rules for D&D. Seeing this come through put me in mind of psionics in general. I've always been a fan and if I play another D&D game (unlikely right now) I will definitely lobby to play a psion or related class.