T Former.js
tFormer.js - Empower your HTML forms
At.js
Add Github like mentions autocomplete to your application.
Fancy Input
Makes typing in input fields fun with CSS3 effects
Validetta
A tiny jquery plugin for validate your forms
Idealforms
The ultimate framework for building and validating responsive HTML5 forms.
Taggle.js
Form-ready dependency-less tagging.
H5F
A JavaScript library that allows you to use the HTML5 Forms chapters new field input types, attributes and constraint validation API in non-supporting browsers.
Tus Jquery Client
A jquery plugin implementing the tus resumable upload protocol.
Switchery
iOS 7 style switches for your checkboxes
Resumable.js
A JavaScript library for providing multiple simultaneous, stable, fault-tolerant and resumable/restartable uploads via the HTML5 File API.
Validatr
Cross Browser HTML5 Form Validation.
Zen Form
Add distraction mode for forms
Inputex
A javascript framework for YUI to build fields and forms.
Signal R
Incredibly simple real-time web for .NET
Jasny Bootstrap
The missing components for your favorite front-end framework.
Formvalidation
The best @jquery plugin to validate form fields. Designed to use with Bootstrap + Zurb Foundation + Pure + Semantic UI + UIKit + Your own frameworks. Star it. Try it. Buy it :)