Is your feature request related to a problem? Please describe.
Its not a problem. just wondering if it would be possible to have a folder that can be used to add custom variants of existing blocks

Describe the solution you'd like
have a folder somewhere (like in .minecraft, perhaps called "custom_rechiseled") where custom variants / textures can be added

just add a texture with the proper name (maybe something like "blockname_variant.png" eg."cobblestone_retro.png") to the folder. then in game there's a new variant of cobblestone added to the UI called "retro" using the texture in the folder