I’m involved in the development of the following APEX plugins. All of these projects are completely open source. Drop me a note if you want to get involved.
The APEX Select2 plugin is based on Select2; an open-source jQuery plugin that greatly improves the functionality and user-friendliness of select lists. In Oracle Application Express, it serves as a replacement for three pre-defined item types: select lists, shuttles and text fields with autocomplete.
This APEX plugin is built on top of Alertify; a lightweight jQuery plugin that introduces elegant browser pop-ups and Growl-like notifications.