After a few years I still use Listary as my main search/launcher. It's very quick, has a very nice look and great system of filters and projects. There are problem with new version to be released, but I'm talking about version number 5.
TMSU - TMSU is a tool for tagging your files.
Keypirinha - A lightning fast and flexible keystroke launcher for Windows. No installation required (portable).
TAGXFS - Tagxfs is a semantic file system. It extends the user space file system to a tag based hierarchy.
Alfred - Alfred is an award-winning app for macOS which boosts your efficiency with hotkeys, keywords, text expansion and more. Search your Mac and the web, and be more productive with custom actions to control your Mac.
Danbooru - Danbooru is an advanced, tag-based image board system that is based on Ruby On Rails.
Wox - An effective launcher for windows. A full-featured launcher, access programs and web contents as you type. Be more productive ever since. Wox is free for use and open-sourced at Github, Try it now! Download .