You should add the license into metadata for the asset packs:
"Edit asset pack->Metadata->Release Info->License for assets" It will increase the size of audience that will be able to find your art
Viewing post in Free Robot Warfare Pack comments
If you think that it was useful for you, you can leave a comment here to support my proposal about making metadata more visible for those who are interested in it https://itch.io/t/2919128/metadata-encouragement#post-7952450