Houserules


Wizards of the Coast’s 3rd Edition D&D

Paizo’s Pathfinder 1st Edition

Onyx Path’s Mage: the Ascension


Mashups


WotC’s 5E D&D / Shadows of the Demon Lord by Schwalb Entertainment

WotC’s AD&D Player’s Options / Ars Magica by Atlas Games

Tweaks