Hello!
You are creating awesome assets
You should add the license into metadata for all your asset packs:
"Edit asset pack->Metadata->Release Info->License for assets"
Viewing post in FREE - Ultimate UI PixelArt Icons comments
You can leave a comment here to support my proposal about making metadata visible for those who are interested in it https://itch.io/t/2919128/metadata-encouragement#post-7952450