ADR Tools : A command-line tool for working with Architecture Decision Records (ADRs).
docopt : Command-line interface description language
how2 : stackoverflow from the terminal.
how2 finds the simplest way to do something in a unix shell. It's like man, but you can query it in natural language.
scmpuff : scmpuff makes working with git from the command line quicker by substituting numeric shortcuts for filenames.
db : With DB you can very easily save, restore, and archive snapshots of your database from the command line. It supports connecting to different database ...
The TLDR pages are a community effort to simplify the beloved man pages with practical examples.