Great question! Thanks.
Commercial use is fine. Please include a credit stating: "Isometric map (or "Isometric maps" if you've used more than one) from Fish in the Pot Isometric Blanks."
Commercial use of these maps is made available via a permissive license from Fish in the Pot which can be revoked at my sole discretion. The sort of thing that will get me to revoke the permissive license is use of the maps in products/materials that are bigoted, racist, homophobic, transphobic, and/or otherwise hateful.
I'd love to see the projects where these maps find a home, so please share a link with me! (I'll probably give it a little twitter boost as well).
--Geoff