The AutoComplete class adds a pulldown menu of suggested values to a text field.
Live Pipe – Extensions for Prototype
LivePipe UI is a suite of high quality widgets and controls for web 2.0 applications built using the Prototype JavaScript Framework. Each control is well tested, highly extensible, fully documented and degrades gracefully for non JavaScript enabled browsers where possible. MIT licensed and actively maintained.
AjaxMGraph

Ajax MGraph – Ajax Graph based on the Prototype javascript library.
Timeframe: Prototype date range component
Stephen Celis got tired of wiring together two date pickers for the common use case of grabbing a date range, so he created timeframe, which is “Click-draggable. Range-makeable. A better calendar.”
ProtoChart

ProtoChart is a new opensource library using Prototype and Canvas to create good looking charts. Features * Line, bar, pie, curve, mix, and area charts available * Multiple data series on same graph * Legend support * Customizable grid, grid border, background * Customizable axis-tick values (both x and y)
qGallery: Prototype gallery application

Sebastian Brink has developed a nice looking gallery application called qGallery It is really simple to use you just have to upload your images in full resolution together with a simple xml file and include the script and a simple div into the webpage. Everything else is done automatically. The gallery is creating every used [...]
ProtoFlow: Coverflow for Prototype

Obaid Ahmed has written a coverflow-like component on top of Prototype and Script.aculo.us called ProtoFlow.
Lightview 2: Not just images, now on Prototype

Lightview was built to change the way you overlay content on a website. * Clean: Designed to compliment your content. * Fast: Smart image preloading. * Easy to customize: You don’t even have to know CSS. * Rounded: Adjustable rounded corners, without PNGs. * Smart resizing: Content will always fit on your screen. * Custom [...]
LiveValidation

LiveValidation is a small open source javascript library for making client-side validation quick, easy, and powerful. It comprises of two main parts. Firstly, it provides developers with a rich set of core validation methods, which can also be used outside the context of forms. Secondly, it provides your visitors with real-time validation information as they [...]
