multi.js is a user-friendly replacement for select boxes with the multiple attribute. It is mobile-friendly, easy to use, and provides search functionality. multi.js is also easy to customize and style with CSS.
vDrop is a minimalistic and customisable jQuery plugin to replace standard HTML select dropdowns.
Pretty Dropdowns is a simple, lightweight jQuery plugin that converts
<select> drop-down menus into "pretty" menus that you can style using CSS. As an extra bonus, it does its best to keep the menu options within the viewport.
Choices.js is a lightweight, configurable selectbox / text input plugin. Similar to Select2 and Selectize.
With Simple Select you can create custom styled select elements by using css and jQuery.
Nice Select is a lightweight jQuery plugin that replaces native select elements with customizable dropdowns.
Searchable Option List is a jQuery plugin which enhances your
<select> HTML elements and makes the options searchable. It works for regular option lists as well as those marked as
Quick[select] is a jQuery plugin for quick selection of common options in select boxes. Quick[select] uses the browser's native select list for its overflow, meaning it will work great on all devices.
A tutorial about creating custom select elements with unique style. It's created by using jQuery and CSS.
A tutorial about creating custom select box by using css and jQuery.
Select2 Bootstrap CSS is a simple css to make select2 widgets fit in with Bootstrap.
Select Multiple is an user-friendly drop-in replacement for the standard select with multiple attribute activated.
Combo Select is a jQuery plugin that converts a select box into a searchable and keyboard friendly interface. Fallbacks to native select on mobile and ipad devices.