and... since i'm thinking about this. The core system is open sourced and called Open D6. There are copies available on Drive Thru that come pre-configured for different game types: space, fantasy, adventure, & a bunch of supplemental material.
I don't like them, and except for the Male Gaze aspect of the covers I can't tell you why. 🤷♀️
Also check out
Lil6 from Chibi (This is a GREAT product, BUT 🙀 it's no longer on DTRPG OR Chibi's site! WHAT HAPPENED⁉️)