Alfred is described as 'productivity application for macOS, which boosts your efficiency with hotkeys, keywords and text expansion. Search your Mac and the web, and control your Mac using custom actions with the Powerpack' and is a well-known app in the OS & Utilities category. There are more than 50 alternatives to Alfred for a variety of platforms, including Mac, Windows, Linux, iPhone and Windows Explorer. The best alternative is Wox, which is both free and Open Source. Other great apps like Alfred are Listary (Freemium), Keypirinha (Free), CerebroApp (Free, Open Source) and Albert (Free, Open Source).
Rocket is an application launcher for KDE Plasma. It sorts all of your applications in a horizontal grid alphabetically, so you will always find what you are looking for at first glance. No more menu navigation, only scrolling.
Copy-paste nicely styled text to apps like GMail and Google Docs without learning new shortcuts. Every time you copy styled text, say from the web, SmartPaste automatically cleans out all unwanted styles, while keeping the useful ones.
LaunchMenu is a free, open source, cross-platform search-based productivity software with similarities to Alfred and Cerebro. LaunchMenu focuses on customisability and extensibility , while also being easy to use through it's one slick interface.