You shouldn’t need an extension to run games with MAGIC and WORLDS; the base ruleset already supports the creating spells/powers with the more advanced system in MAGIC. The content isn’t there, but the framework to create and use that content is there.
I’ve also made extensions (mods, basically) to support the rules modifications in Altered State (surge, rage, different effort, etc), as well as Blood & Snow (using armor to soak damage instead of as a target to hit). I’ll be sharing those shortly.
As for book modules, I would love to get all the WORLDS, MAGIC, Altered State, Blood & Snow, etc. content out there, but that’s up to Hank. Of course if he’s ok with it, we could just share all that content here for free rather than putting it up on the store, but it’s his content.
Since it sounds like 3e is on the horizons, I might see if we can get an official FG module for 3e which should contain the best of everything up to now.