Some scammers can get quite creative so it's impossible to list all the scams in existence. But all scams have one thing in common - they always require you to send your money first and in return get some profit. When you see an opportunity like that, you should get very-very suspicious and very carefully examine it. There's very little legitimate opportunities that work like that, for example casino bankroll investment or yield farming, but even these things could be ran by scammers.

IMO it's not a good idea to try to invest your hard earned bitcoins, Bitcoin already provides tremendous growth, why be greedy and risk losing it?