Official System Reference Documents for other game systems can be found here. These SRDs are released under the Open Game License v1.0a.

• Pathfinder (1E) Reference Document (compiled by Mike Dusseault)

• 13th Age (Archmage Engine) SRD

• Revised (v3.5) System Reference Document

• d20 Modern System Reference Document (includes d20 Modern, Urban Arcana, d20 Future, Menace Manual)

• Fate Accerated Edition SRD

• Traveller System Reference Document