A simple 35x35 mm bracket with cap to hide the mounting screw for mounting furniture to the wall. What I really like about printed brackets is that you can print them in any color you like.
The bracket is 35x35x4 mm. Print with 100% infill and lying on its side for maximum strength. They turn out surprisingly strong. However, remember, this is not steel, so don't use them e.g. for upper kitchen shelves.
I use flat head crews (12 mm head diameter) for mounting to the wall and three countersunk 3x15 mm screws for attaching the bracket to the shelf.
Generic PLA or ABS
Any you like
Designed in FreeCAD 0.18