This app was mentioned in 4 comments, with an average of 2.50 upvotes
There's a ton a great street art around Toronto on Graffmap! Android and iOS
Also relevant:
https://streetart.withgoogle.com/en/world-collection
https://play.google.com/store/apps/details?id=com.guarana.graffmap.app&hl=en // https://itunes.apple.com/ca/app/graffmap/id884867249?mt=8
https://wall2wallmtl.com/walking-tour-tour-pedestre/
You should check out Graffmap for iOS or Android
I used https://play.google.com/store/apps/details?id=com.guarana.graffmap.app a few years ago. Just reinstalled it. It doesn't appear to be very active in my neighborhood.