Checkboxland is a JavaScript library for rendering anything as HTML checkboxes. You can use it to display animations, text, and arbitrary data. It also supports plugins, so you can build more powerful APIs on top of it. Checkboxland is dependency-free, framework-agnostic, and fun! 🙃

Tumult Whisk is the lightweight HTML and PHP editor with a live preview pane that displays the updated page as you type. It is an essential app for your web dev toolkit.

Sounds stupid and listy but it's actually a good introduction to some of the more useful and practical pieces of the huge insane HTML5 Boilerplate (html5boilerplate.com).

As seen on Normative.com.

Ugly "Browse..." buttons be gone!