To name a few, we are all aware of things like :
- Fake Wallets
- Ponzi Schemes
- Fake Giveaways
- Phishing Attempts to get us deceived
- Being a victim of some hack
- Investments is fake shitcoins and other fake websites
I have never lost any BTC to any of the listed options above... Maybe because I am extra careful.
I have, however lost about 0.1 BTC when i was just getting started with futures trading mostly. At the beginning i lost some when i was learning spot trading to it was around $100.