Its standard D&D, and I use some of the FR deities for the pantheon because I love that pantheon (but there's some weird twists in that too...). I also allow almost everything Wizards (or reasonable d20) into it, which I guess is non-standard, with the understanding that the DM can use all that stuff too for crazy bad guys. Cosmology is mostly 2e Planescape (so the Astral and Ethereal are perpendicular, dammit!). And Psionics is Different, but there is only one psion (and his apprentice), and you can't be them. There's a good in-game reason for this involving the Far Realms and iillithids. Also, anyone in this world is required to know and hate a foul villain known as Dhistan Moonshadow (former PC, went to the dark side and was super-evil).