[windowojji]

For other small JS engines similar to QuickJS see Hermes: https://github.com/facebook/hermes

[filleduchaos]

Hermes is far from a small JS engine (and is not really similar to QuickJS at all).

Duktape, Espruino and JerryScript are way closer examples (both in size and spirit).

[flanbiscuit]

Fitbit uses Jerryscript in some of their watch OSes. Well, at least they were last time I was tinkering with making my own watch face

https://jerryscript.net/