Avoid them. YouTube videos promising a key list in the description are almost always scams. They typically:
Shared keys are frequently deactivated by Microsoft once they are identified as being used across multiple unauthorized devices. Microsoft Support How to Find Your Legitimate Product Key microsoft office 2019 product key list
The search for a is a trap. No legitimate list exists. Every free key you find will either be blocked, temporary, or a vehicle for malware. The time you waste hunting for a free key, plus the cost of cleaning an infected PC, far exceeds the $150 price of a genuine license. Avoid them