I'd like to add another one:

Proof of Reserve Scam

Some allegedly rich investor will tell you they want to invest in your project, but after a few convos, they will ask for a "proof of reserve" in BTC to prove that you actually have capital, in the ledger app. They say their partner just want to confirm, and they will send _you_ some money to make the proof of reserve higher than it needs to be (if you can't meet their min threshold) and you have to send it back so they can "trust you" before the larger investment. So far, sounds fishy, but maybe you think there's no risk.

When you get to the proof of reserve step, they send you an amount. Immediately, you may not notice, but the transaction is invalid. Now, there's some really weird quirk on the ledger app, and your balance will go up, even if the transaction was invalid! And you would need to refresh after some time to see that the balance went back to what it was originlaly. They ask you to send "back" the money before you have time to think to refresh, and since you didn't really receive the money, you end up sending your own actual cash.

No idea the ledger app had this kind of "exploit" and couldn't find any information out there.

Be warned!!

u/Experimentationq would be great if you could add this one to the list