The author of More Block Predicates has given permission to use their project (yippie!)

Having something like this up-to-date would be absolutely amazing for resource pack creators

omoflop/MoreBlockPredicates#24

I'm currently working on it, though it's harder to port than I expected, due to recent changes in 1.21.5, as well as the need for cross-loader support.
I'll figure it out eventually :)