What a great collection! We have talked months ago about the sticker art. I too have some photos from stickers that I've found in Porto city, but I must confess that they aren't as cool has the ones that you presented here! The QR code is indeed a door to a place that could be very dangerous 😅 I'm sure that I would scan it 😅
My favorite ones are the portrait with the amazing color pallet and also that psychedelic cat!
Have a great weekend!