Also UL94 (https://www.swiftfuelsavgas.com/) could be used in many models. Unfortunately some have been previously upgraded to high-compression engines to get a few more horsepower and they can't use UL94.

Some can run on ethanol-free 87-octane automotive fuel, generally the low-compression engines that already can run 80/87 aviation fuel.

80/87 and 100/130 leaded fuels are all but unavailable, but 100LL is ubiquitous. There is a chicken and egg problem to make G100UL and UL94 available, which will encourage its use. Even automotive fuel is hard to find at airports, possibly because they don't want the liability of improper fueling. (100LL is compatible with almost every gasoline aircraft engine, the rest are not.)

The G100UL also may have an issue with being too good of a solvent, although the developer insists that's a libel.

Swift Fuels is also supposed to introduce a different type of 100-octane unleaded called 100R that has had good results in testing but hasn't been broadly approved yet.

It was like pulling teeth from a dragon to get the FAA to move forward with G100UL as I understand it, and then they suddenly approved it for just about anything provided they write a supplemental type certificate. So maybe the same will happen when/if 100R is approved and someone will handle the marketing.