By using the plugins you could add countdown to your website without write a lot of style and scripts. These plugins include css and js files so you don’t need to worry about scripts or styles.
Smart Timer And Counter
Smart Timer And Counter is a jQuery plugin that can be used to add timers and clocks to the web page.
jQuery Responsive Countdown with Visual Builder
This is a javascript based tool that uses the canvas object to animate SVG defined drawings.
Count Everest Countdown | Responsive jQuery Plugin
jQuery Countdown
CountDown jQuery plugin
jQuery Countdown plugin that doesn’t sucks!
JCountdown Pro Plugin
This Pack contains Unlimited designs of countdown rings which can be generated by simply putting random numeric value.
jQuery Countdown Plugin
KK Countdown
The Final Countdown plugin for jQuery
Coconut - Jquery Countdown Plugin
The countdown is a jQuery plugin that comes with many powerful features, the template its very easy to skin with any image or color.
Fancy Countdown
jQuery Flipclock
Simple countdown
Flexible and easy to setup jQuery “countdown” clock
Fancy Countdown - jQuery plugin
Fancy Countdown is a highly customizable jQuery plugin that lets you create an outstanding countdown.
jQuery Count Down
There are numerous times when you need a count down timer. This can be done without jQuery but with many websites using jQuery, why not write this tutorial for it 
jQuery Countdown
This is a jQuery plugin that sets a div or span to show a countdown to a given time. There are tons of options available and everything is supported by good examples and code snippets. 
jquery countdown by kemar
Unobtrusive and easily skinable countdown jQuery plugin generating a time tag
littlewebthings CountDown
This is an Easy to use animated countdown Javascript. It is jQuery compatible and easily.
jQuery Knob
Nice, downward compatible, touchable, jQuery dial
jquery-countdown
Circular Countdown jQuery Plugin
This plugin mixes a jQuery countdown combined with canvas shapes easy to configure via a set of options.
