Keypirinha - A lightning fast and flexible keystroke launcher for Windows. No installation required (portable).
TLDR pages - The TLDR pages are a community effort to simplify the beloved man pages with practical examples.
Listary - Listary is a revolutionary search utility for Windows
CheatKeys - View Windows keyboard shortcuts in the current application.
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.
explainshell - Match command-line arguments to their help.