We did this nearly seven years ago, so let's get it going again.
This is the place where you can share whatever QR codes you create or find (give credit where credit is due!). For those that don't know, these user created designs can be placed on all kinds of things in the game (shirts, wallpapers, floor tiles, art easels, mugs, etc.)
Nintendo has stated that QR codes from New Leaf and Happy Home Designer will work in the new game. So, if you have any old QR codes lying around, share those too. The old game's designs are all 32x32 pixels. We don't know for sure yet what New Horizon's limitations are.
And since the old codes work, make sure to check out the New Leaf QR Code thread for even more stuff including classics like the Whiskey Media Members shirt, Ryan Davis as Pikachu, a Chie jacket, and so much more.