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).
Stonly Knowledge Base - Interactive knowledge bases and help-centers
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.
Free Knowledge Base by Dashly - Optimize your customer support with Knowledge Base by Dashly
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 .
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.