Game Green with Highlighted Tab от Twijg

A thorough Gaming theme with Highlighted current tab and a dark look with strong accents. Designed for gamers.
Special is the strong, green current tab.

At the moment, it is not possible to change the color of the circle around the back button, if it bothers you, try changing the lay-out to "compact". I have filed a feature request to include this in the web extensions API.