EDIT: I’ve made the Oppo adaptive icon! Well, sort of. The hackjob (for now) is to make an image that looks similar enough to my adaptive icon style. Maybe one day Nova Launcher will support 100% custom adaptive icons. For now, feel free to snag the files at this Google Drive link. If you’re handy with something like Inkscape, you can tweak the SVG file to your liking, then export it at a nice big resolution that makes it look good on your phone. If you’re not handy with SVG icons, just crop the base image into the shape of your adaptive icon (though I feel sorry for you if you have squircles like Samsung phones. Squircles. Such a weird word.)
Bonus screenshot of my homescreen with the Oppo icon so you can see how it looks (be prepared to scroll, whoops):
Original post follows: I’m looking to make an Oppo icon in the style of a Google adaptive icon to blend in with my homescreen. If you have a vector handy, that’d be awesome, but if not, a high res image works and I’ll just vectorize from there.