I felt that the Nest thermostat looked kind of bare on the wall alone, and there is a trim plate that comes with it but I felt it had no visual style. So I was on a quest to find a wall plate for it but there is a very limited amount (very few) and I also found myself not liking the few styles out there for sale online.
I went to IKEA and purchased a mini bamboo cutting board called APTITLIG which I sliced in half with a table saw so I can cut a circle but I didn’t want the gap between the thermostat and the edge of the circle to expose the wall color from behind, so only the front half was circle sawed and the back half was left alone except for the mounting holes and a smaller center hole to run the wires through.
After cutting all the holes I used wood clue and clamps to join the 2 halves back together. Now the thermostat sits recessed in the board and the thermostat has a little more visual interest on the wall.