Hah! Tons. This is why most hodlers long ago learned never to use centralized exchanges. Bitcoin is a trustless medium of exchange - why would you trust a third party to hold your coins?

To name a few Mt. Gox, FTX have "lost"/stolen people's funds.
Coinbase and Binance have both had periods where they hold peoples funds and delay/prevent withdrawals.

Rule of thumb: "Not your keys, not your coins." That means if you trust a third-party with your private Bitcoin wallet keys (or any other crypto), you no longer own those coins and have to trust that third party to A. never lose them B. Never steal them C. Never have them stolen.

There are many ways to safeguard your coins and keep them yourself. Research them.