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.
Geocomplete is an advanced jQuery plugin that wraps the Google Maps API's Geocoding and Places Autocomplete services.
You simply provide an input that lets you search for locations with a nice autocomplete dropdown. Optionally add a container to show an interactive map and a form that will be populated with the address details.
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.
ajaxComboBox is a jQuery plugin for creating a text box it can "autocomplete" and "pulldown select".
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.
AutoJS is a library to continuously autocomplete textarea based on a standard dictionary. Dictionary has been deviced based on researches and linguistic methods, keeping an eye on minimizing the size of the library. Complete project is written in plain js, with no external dependencies, and it's size is reduced to mere 6kb.