I have a shelf attached to a wall in my garage where I have a mini PC, Monitor, Mouse, and a Keyboard. The shelf is narrow as I didn't want it sticking out far. The monitor stand left no room for the keyboard so I made this shelf bracket for my keyboard so it hangs off the shelf and is raised above the monitor stand. The brackets are sized for a shelf of 5/8 thickness.

I used some stick on thin felt circles on the inside of the bracket and the top where the keyboard goes. This prevents the bracket and the keyboard from moving.