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.
Keypirinha - A lightning fast and flexible keystroke launcher for Windows. No installation required (portable).
Cairo-Dock - Cairo-Dock / GLX-Dock 3. 4 is now available. Cairo-Dock 3. 4 is finally released! One year after the 3.
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.
Gnome-Pie - Gnome-Pie is a circular application launcher for Linux.
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 .
Synapse - Synapse is a semantic launcher written in Vala that you can use to start applications as well as find and access relevant documents and files by making use of the Zeitgeist engine.