Ridiculously Responsive Social Sharing Buttons is built with SASS, so you can easily customize it by tweaking a few variables. SVGs allow for tiny file size and retina support. Add or remove icons as you see fit — the rest will fill in automagically in the container.
ClassyCountdown is a jQuery plugin to easily create clean circular countdowns. It is fully customizable and includes 12 themes, which can be modified and it uses HTML5 canvas for rendering the circles.