I'm a long time user of quicksilver. Open source. Long time loyal users swear by its ux for efficiency. Development has slowed down recently, but it still runs great for me.

https://qsapp.com/index.php

Nope, and I've been searching.

The issue with the spotlight engine that everyone uses is that it excludes "hidden" directories and in particular every dot file and dot directory.

Spotlight is built in, but Alfred’s also a good one.