Horsey is a progressive and customizable autocomplete component. It supports every sane browser and IE7+.
Awesomplete is an ultra lightweight, customizable, simple autocomplete widget with zero dependencies, built with modern standards for modern browsers.
jQuery Autocomplete plugin is a lightweight simple and easy in settings autocomplete like Google.
Autocomplete.js is jQuery plugin that improve your search with hints. Autocomplete.js also has some options to customize.
It gives a search preview from Json object(s) via same domain Ajax request or cross domain jsonp and offers data compression inside Local Storage.
Autocomplete Table is a jQuery plugin that provides suggestions from a multi-column table in a dropdown list while the visitors type into the input field.
Flexselect is a jQuery plugin that turns regular select boxes into Quicksilver-like, flex-matching, incremental-finding controls.
Autocompleter is a simple, easy, customisable autocomplete plugin with cache support (one more alternative).
Marco Polo is a jQuery autocomplete plugin for the discerning developer.
typeahead.js is a fast and fully-featured autocomplete library that is inspired by Twitter's autocomplete search functionality.
Ajax Autocomplete for jQuery allows you to easily create autocomplete/autosuggest boxes for text input fields.
Built with focus on performance - results for every query are cached and pulled from local cache for the same repeating query. If there are no results for particular query it stops sending requests to the server for other queries with the same root.
Inputosaurus Text is a jQuery plugin that allows for multiple delimited values, parse hooks, autocomplete, keyboard shortcuts etc.
The jQuery Tagit plugin transforms an html unordered list into a unique tagging plugin. Why unique? Because jQuery Tagit uses jQuery Ui's auto-complete plugin to supply suggestions to users as they type.