What are some alternatives?
When comparing YouTube Time Tracker Extension and YouTube Rabbit Hole, you can also consider the following products
Futuramo Time Tracker - Futuramo Time Tracker is a time tracking solutions designed for freelancers and teams.
Focus - New Tab page that gives you a moment of calm and inspires you to be more productive.
SaveMyTime - Time Tracker - The whole picture how you spend time. Both online and offline activities.
Go Fucking Work - Website blocker so you can get back to your fucking work
Invideo for Youtube - Search inside Youtube videos (think Ctrl-F)
Hyperfocus - The distraction blocker for macOS