What superhero ttrpgs have creative commons/open licenses?

[Libertad]

I've been thinking about creating 3rd party material for superhero rpgs, but I am not as familiar with their licenses in comparison to D&D and related fantasy iterations. I am aware that Mutants & Masterminds operated under the OGL, Aberrant/Trinity Continuum has an Approved Licensing Program, and Marvel Superhero's FASERIP system has been used by various publishers, but don't know or have found similar licenses for other superhero ttrpgs.

What's out there for third party creators?

 

[Alzrius]

Silver Age Sentinels is also an OGL superhero TTRPG.

EDIT: Rather, the d20 version of the game is.

 

[dbolack]

Bulletproof Blues is CC-By-SA
Icons is OGL with a compatibility license
Mutants and Masterminds is OGL plus has the Powered by Mutants and Masterminds program
Hero Kids has a Supers variant that is also licensed ( Creator's Guild )

 

[jdrakeh]

Four Color System (Core Rules)​