WatchOS for the Arduino
This is a project I made back in 2017. I had the initial goal of creating a fully functioning OS to put on your watch where you could play games and stuff, but I was never able to finish it. I did pick up the project again this year and attempted a much more advanced rewrite (at least compared to my novice programming in the older projects), but I still haven't added all I want to add and probably won't any time soon. If you're interested in using this project, the main branch is the folder WatchOS, and it's using an ESP8266 with a joystick, Adafruit SSD1331 screen, a DS1307 clock, a button and a speaker. Some of the issues are screen clearing and being very slow, but I think it's definitely fixable. Also, I use a weird configuration for the joystick since the ESP8266 only has one analog pin that I could use, so you will need a couple resistors and to calibrate a couple variables I think. Alternatively, you could buy an I2C analog extension and connect the joystick that way.
Some examples of things I wanted to add but haven't are a News (RSS?) reader using the WiFi feature, a snake game, Something based on Among Us (haha), and flappy bird type game
Also make sure to fill in your own WiFi SSID and password if you want syncing the real time.