Elmore’s Sovereign Stone Codex Mysterium D20 Sovereign Press

The Codex Mysterium provides a good system for replacing the basic D20 system. I've never liked AD&D's memorizing spells, and have often come up with home-grown systems or use other third party systems. The problem is, memorized spells just don't match the way most fiction portrays magic. You never get to the point where you can just do simple spells with a thought, like you can with the GURPS system.

The Codex's system provides the ability to get to that point, and does it without sacrificing game balance. It balances the ability to cast unlimited spells per day with the chance of failure and a potential cost in hit points for overdoing it.