Guard::RSpec automatically run your specs (much like autotest).

Guard::LiveReload automatically reloads your browser when 'view' files are modified.

Automatically rebuilds Nanoc sites

Guard::Minitest automatically run your tests with Minitest framework (much like autotest)

Guard::Bundler automatically install/update your gem bundle when needed

Guard::Jasmine automatically tests your Jasmine specs on PhantomJS

Guard::Spork automatically manage Spork DRb servers.

Restart Rails when things change in your app

Guard::Cucumber automatically run your features (much like autotest)

Guard::Brakeman automatically scans your Rails app for vulnerabilities using the Brakeman scanner: https://github.com/presidentbeef/brakeman

Guard::Shell automatically runs shell commands when watched files are modified.

Guard::Spring automatically manages spring process.

Guard::Test automatically run your tests on file modification.

Guard::CtagsBundler uses ctags utility and generates 2 files: tags -- with tags generated from project's source tree and gems.tags -- with tags generated from rubygems from project's bundle.

Restart puma when files change

Guard::Zeus automatically manage zeus

Guard::CoffeeScript automatically generates your JavaScripts from your CoffeeScripts

A Guard plugin for smarter Jekyll watching

Guard::Less automatically compiles less (like lessc --watch)

Guard::Migrate automatically runs your database migrations when needed