Basic Roleplaying: Universal Game Engine
Motor universal d100 de Chaosium. Tiradas porcentuales roll-under, grados de éxito, características 3–18, habilidades que mejoran con el uso, combate reactivo y módulos opcionales para distintos géneros.
Free
Fantasía · d100
Roliando is a free virtual tabletop for playing roleplaying games online: tactical map, sheets that do the maths themselves, dice and voice. Besides these systems, you can build your own without writing code.
Each system is published here with its author’s permission or under a licence that allows it; the specific credit and licence are on its page inside Roliando.