ChessClock+

ChessClock+ is a simple, highly customizable chess clock extension for Chrome. It makes it easy to add time controls to any chess game, with per-player clocks, multi-phase timing, and support for Fischer, Bronstein, and delay.

Key features include hourglass mode that transfers expended time to the opponent, multiple presets (and the ability to create your own), customizable alerts, colors, and clock orientation—all wrapped in a clean, user-friendly interface.