Some mods have "exotic" stone types with decorative variants (such as Scoria, Jasper, or Slate, from Create or Oh The Biomes You'll Go) that are not natively supported by Chisel.

Since there could be a lot of them, it would be practical to have some way to specify new tags to be chiselable (be it through, config, datapacks, KubeJS, Crafttweaker, or whatever) rather than PRing a bunch of otherwise useless tags (since Chisel itself does not add those stones). There is apparently no way to do that on 1.16.5.

Linking the issue that prompted this suggestion. EnigmaticaModpacks/Enigmatica6#3668