zsh - The Z shell (Zsh) is a Unix shell that can be used as an interactive login shell and as a powerful command interpreter for shell scripting.
TLDR pages - The TLDR pages are a community effort to simplify the beloved man pages with practical examples.
GNU Bourne Again SHell - Bash is the shell, or command language interpreter, that will appear in the GNU operating system.
explainshell - Match command-line arguments to their help.
fish shell - The friendly interactive shell.
cheat - Cheat allows you to create and view interactive cheatsheets on the command-line.