Good catch, added MIT license - feel free to use it! On top of that, my understanding is that math/equations are not subject to copyright, so the core part of this work (the equations/ideas) I think legally has 0 limitations - even if there were a restrictive license. But IANAL so might have some misconceptions.

Procedural generators are often free if you look around for a bit.

https://kuhantilope.gumroad.com/l/ultimate-skin

https://extensions.blender.org/add-ons/mpfb/

https://github.com/alessandro-zomparelli/tissue

ymmv, as some paid plugins actually speed up the funky blender workflow (the auto-Bake plugin by the same author is important for procedural generated textures.)

https://sanctus.gumroad.com/l/SLibrary?layout=profile

Have a great day =3