My Lack floating shelf eventually starting sagging off the wall. Because I am lazy, I used toggle bolts which are much stronger in drywall but the screw head diameters for most sturdy ones are too large in diameter for the floating shelf brackets, so I made these.

Bear in mind, these are plastic so don't go Tarzan slamming the shelf onto the bolts, but they do hold well as it's been several months and my dog is still sitting on the shelf without falling off.

Profile is 5 walls, you'll need em…or maybe not but why not, it's a 13 minute print for two.