This is a shelf bracket I made for a glass shelf behind my bar. 3 of these are currently holding a 36x16x3/8" piece of glass with several bottles on top of it. They are extremely sturdy. Designed for 3/8" inch glass, but could work for thinner if needed.

Due to the glass I used being 16" hanging out from the wall I printed the two outer at 100% infill and the middle at 50% infill. If you used a 12" piece of glass, you could probably do 30% infill across the board without issue.