Smaller scale but I have $10k in Bitcoin locked in an encrypted file that I also lost the password to. Bought it for like $100 8 years ago. I can try as much as I want but no luck yet. Keeps me up sometimes.
Even smaller scale, in 2014 I converted some dogecoin to 0.05 BTC, then moved the BTC into a brainwallet. I have not been able to remember the key ever since. Now it's worth $1600.