Selectize is the hybrid of a textbox and <select> box. It's jQuery based, and it has autocomplete and native-feeling keyboard navigation; useful for tagging, contact lists, etc.

💳 make your credit card form better in one line of code

📫 SMTP Server + Web Interface for viewing and testing emails during development.

Modern framework to print the web correctly.                                               

Native dual range input in 60 lines of JavaScript.