Quill
A cross browser rich text editor with an API
Selectize.js
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.
Filepond
🌊 A flexible and fun JavaScript file upload library
Alpine
A rugged, minimal framework for composing JavaScript behavior in your markup.
Switchery
iOS 7 style switches for your checkboxes
Angular Validation
Customizing Form Valid Message in AngularJS
Form2js
Javascript library for collecting form data
Fancy Input
Makes typing in input fields fun with CSS3 effects
Angular Formly
JavaScript powered forms for AngularJS
React Editext
Editable Text Component for React Apps
jQuery Autotab
A jQuery plugin that provides auto tabbing and filtering on text fields in a form
Sisyphus
Gmail-like client-side drafts and bit more. Plugin developed to save html forms data to LocalStorage to restore them after browser crashes, tabs closings and other disasters.
Forms Angular
Probably the most opinionated framework in the world
Multi Select
A user-friendlier drop-in replacement for the standard select with multiple attribute activated.
Magicsuggest
Multiple Selection Combo Box using Bootstrap 3
jQuery Steps
A powerful jQuery wizard plugin that supports accessibility and HTML5.
Unform
Performance-focused API for React forms 🚀