LoopOne for YouTube од EasyPlugins

Adds a repeat button directly into the YouTube player's right-side controls. Click the button or press R to toggle single-video looping on and off.

Features:
One-click repeat toggle in the player controls
Visual indicator: icon turns red with "1" when loop is active
Keyboard shortcut: R
Remembers your repeat preference between sessions
Works in fullscreen mode

The extension works only on youtube.com video pages. The only data stored is your on/off preference (locally in the browser). No data is collected or transmitted.