My personal list of delightful Bash scripts and resources.
In addition to this list, consider reading awesome-shell, awesome-zsh or awesome-fish.
- shdoc - Documentation generator for shell scripts.
 - jqmd - Write and document your jq/shell scripts with markdown.
 - zshelldoc - Doxygen For Shell Scripts.
 
- mkdkr - Make + Docker + Shell = CI Pipeline.
 - todo.sh - A simple and extensible shell script for managing your todo.txt file.
 - homeshick - Git dotfile synchronizer written in Bash.
 - bashblog (original) - A Bash script that handles blog posting.
 - fff (original).
 - neofetch (original).
 - pfetch (original).
 - Dropbox-Uploader - Dropbox Uploader is a Bash script which can be used to upload, download, list or delete files from Dropbox
 - xiringuito - SSH-based "VPN for poors".
 
- bocker (original) - Docker implemented in 100 lines of bash.
 - bash2048 - Bash implementation of 2048 game.
 - spark (original).
 - Bash-script - Bash scripts.
 - bashlets - An experiment in extending the command-line interface.
 
- bash-stack - modern web framework in bash.
 - sherver - Pure Bash lightweight web server.
 - bashttpd - A web server written in Bash.
 - ngincat - Tiny Bash HTTP server using netcat.
 - balls - Bash on Balls.
 
- bats - Bash Automated Testing System.
 - shunit2 - shUnit2 is a xUnit based unit test framework for Bourne based shell scripts.
 - assert.sh - Bash unit testing framework.
 - bash_unit - Bash unit testing enterprise edition framework for professionals.
 - bunit - A unit testing framework for Shell scripts - namely Bash.
 - assert.sh (original).
 - test-runner.bash - Integrations Test Runner for tests.sh.
 
- mo - Mustache templates in pure Bash.
 - ansi - ANSI escape codes in pure bash - change text color, position the cursor, much more.
 - argbash - Bash argument parsing code generator.
 - semver_bash - Semantic Versioning in Bash.
 - shellfire (original)
 - bashful (original)
 - mkdkr (original)
 - JSON.sh (original)
 - JSONPath.sh (original)
 - TickTick (original)
 - resholve - Shell resolver.
 - bashup/mdsh - Multi-lingual, Markdown-based Literate Programming... in run-anywhere bash.
 - bashup/events - An event/callback/promise system for bash apps that's fast (10k/s), tiny (<2.2K), and portable (bash 3.2+, builtins-only)
 - bashup/realpaths - Fast, portable path manipulation and symlink resolution in 2K of pure bash
 
- modernish - Modernish is a library for writing robust, portable, readable, and powerful programs for POSIX-based shells and utilities.
 - bash-oo-framework (original)
 - bash3boilerplate - Templates to write better Bash scripts.
 - bashful - A collection of libraries to simplify writing Bash scripts.
 - bashly - Bash command line framework and CLI generator.
 - Bashmatic - An easy to use DSL library for building BASH-based tooling & installers (900+ functions).
 - Bash Infinity - A modern boilerplate / framework / standard library for bash.
 - bash-modules - A collection of modules for unofficial strict mode.
 - ebash - enhanced bash.
 - bash-lib - Library for bash utility methods and tools.
 - DevOps-Bash-tools - 750+ DevOps Shell Scripts and Advanced Bash environment.
 
- bashify - Few helper functions in bash (especially string manipulation functions).
 - async-bash - Implementation of async functions in bash.
 - emitter - Event listeners for bash.
 - furious-bash - Furious is a bash script that benchmarks bunch of functions, and gives you the ability to be able to extract the fastest or slowest function.
 
- mvdan/sh - A shell parser, formatter, and interpreter with bash support; includes shfmt.
 - shellcheck - A static analysis tool for shell scripts.
 - shellharden - The corrective bash syntax highlighter.
 - kcov - Code coverage tool for compiled programs, Python and Bash.
 
- bash-preexec - zap preexec and precmd functions for Bash just like Zsh.
 - bleh.sh - Bash Line Editor―a full-featured line editor written in pure Bash!
 - bash-completion - Programmable completion functions for bash.
 
- bash-git-prompt - An informative and fancy Bash prompt for Git users
 - bash-powerline - Powerline-style Bash prompt in pure Bash script
 - bashstrap - A quick way to spruce up OSX terminal
 - git-prompt - Bash prompt with Git, SVN and HG modules
 - liquidprompt - A full-featured & carefully designed adaptive prompt for Bash & Zsh
 - oh-my-git - An opinionated git prompt for bash and zsh
 - sexy-bash-prompt - Bash prompt with colors, Git statuses, and Git branches
 - bash-sensible - An attempt at saner Bash defaults
 
- aliases - Contextual, dynamic, organized aliases for the bash shell.
 - bashhub - ☁️ Bash history in the cloud. Indexed and searchable.
 - bashhub-server - Privately hosted open source bashhub server.
 - bashmarks - Directory bookmarks for the shell.
 - commacd - A faster way to move around in Bash.
 - has - 
hashelps you check presence of various command line tools and their versions on path. - hstr - Bash History Suggest Box.
 - sshrc - Bring your .bashrc, .vimrc, etc. with you when you SSH.
 - zoxide - A better way to navigate your filesystem. Written in Rust, cross-shell, and much faster than other autojumpers.
 
- basher - A package manager for shell scripts.
 - bpkg - A lightweight bash package manager.
 - basalt - The rock-solid Bash package manager.
 - ash - 🐚 A Modular Bash Framework.
 - import.bash Golang-like import statement in bash.
 - bpm (original).
 
- bash-it - A community Bash framework.
 - oh-my-bash - A delightful community-driven framework for managing your bash configuration, and an auto-update tool so that makes it easy to keep up with the latest updates from the community.
 
- Stack Overflow - Bash tag on Stack Overflow
 - /r/bash - A subreddit dedicated to bash scripting
 - /r/commandline - for anything regarding the command line, in any operating system
 - #bash - IRC channel on Libera.Chat. The main contributors of the BashGuide, BashFAQ, BashPitfalls and ShellCheck hang around there
 
- The Bash-Hackers Wiki - Human-readable documentation of any kind about GNU Bash.
 - Bash beginner's mistakes (by the Bash-Hackers Wiki).
 - Bash Guide - A bash guide for beginners. (by Lhunath)
 - Bash FAQ - Answers most of your questions (by Lhunath)
 - Bash Pitfalls - Lists the common pitfalls beginners fall into, and how to avoid them
 - Bash manual - Bourne-Again Shell manual
 - Advanced Bash-Scripting Guide - An in-depth exploration of the art of shell scripting.
 - Bash Guide for Beginners (by Machtelt Garrels).
 - Bash Programming - Intro/How-to
 - bash-handbook - A handbook for those who want to learn Bash without diving in too deeply
 - Google's Shell Style Guide - Reasonable advice about code style.
 - Sobell's Book - A practical guide to commands, editors, and shell programming.
 - WikiBooks: Bash Shell Scripting.
 - Use the Unofficial Bash Strict Mode (Unless You Looove Debugging)
 - Defensive BASH Programming - Methods to defend your programs from breaking as well as keeping the code tidy and clean.
 - Pure Bash Bible - A collection of pure bash alternatives to external processes.
 
Credit to whetu on Reddit for this post.