Fuzzy searching for the assets window of my engine. It was simpler to implement than I expected. At first I looked into various matching algorithms, but then I checked how rxi did it in Lite and it was a very simple matching function which produces good enough results. It's great to have these high quality open source projects to use as a reference!
Lite's function: https://github.com/rxi/lite/blob/38bd9b3326c02e43f244623f97a622b11f074415/src/api/system.c#L356