BlockUI

Simulate synchronous ajax by blocking – not locking – the UI. This plugin lets you block user interaction with the page or with a specific element on the page. Also great at displaying modal dialogs.

BEM helpers for jQuery

Provides a set of helper methods to support BEM Methodology (http://bem.info) in your projects.

jQuery Browser Select Dialog

This plugin allows you to show a dialog to upgrade user browser when it is not upto the required specification. This is mainly used to retire older version of IE users to upgrade to later new versions or prompt them to use different and better browser.