Homebrew - The missing package manager for macOS
Chocolatey - The sane way to manage software on Windows.
SuperGamer - SuperGamer is a live DVD currently based on Ubuntu (previously it was based on VectorLinux), intended to showcase gaming on Linux.
Scoop - A command-line installer for Windows
Linuxbrew - The Homebrew package manager for Linux
Ninite - Ninite is the easiest way to install software.