Decided to try my own generatively designed shelf bracket that is easy to print and mount. I designed it to support a minimum of 50 lbs./bracket and I have been able to exceed this in testing using PLA with 2 perimeters and 20% grid infill. I recommend using adaptive layers to deal with overhangs and a brim as well.
Requires:
Approximately 6.5" deep shelf plank (165mm)
2x #8 wood screws per bracket
Adhesive to secure shelf - I used construction adhesive.
The author hasn't provided the model origin yet.