Select2 is a jQuery based replacement for select boxes. It supports searching, remote data sets, and infinite scrolling of results.
Creates nestable menus.
MagicSuggest is a multiple selection auto suggest combo box for Bootstrap 3.
Renders a scrollable list from HTML selects for easy data picking on touch devices. It comes with theming capability, optional jQuery Mobile integration and multiple display modes: Inline, Modal, Bubble, Docked Top & Bottom. It works with optgroups as well.
Yet another jQuery plugin to style/replace select elements.
Fast, simple and light jQuery plugin to customize HTML selects
Superfish is a jQuery plugin that adds usability enhancements to multi-level drop-down menus. Fully supports touch devices and keyboard interaction.
jQuery plugin that turns select boxes into flex-matching incremental-finding controls.
Customizable replacement for html select (not only) with events, callbacks, themes and much more.