My Apple TV quickly accumulated dust while it was sitting under my TV. I wanted a holder that I could attach to either the wall, VEGA mounting brackets on the back of the TV, or use 3M Command Strips depending on where the TV and Apple TV were located. I originally searched but the options available were either too expensive or did not fit my needs. I decided to make my own; and why not, I had just received my very first i3 MK3S weeks before. 

The Apple TV slides into the holder with appropriate clearance, has vents to allow for cooling, and a cable area on the bottom for HDMI, power, or LAN cables.  

The original design has a center hole for mounting to a wall or TV stand. A later iteration uses a DIN mount to securely hold the Apple TV. 

I print these in PETG and PLA with supports in place and then remove the supports. If you have a MMU2S, other multi-filament device, or a dual extruder machine, you could use dissolvable supports. I didn't find that necessary.