Most of them are probably scam but for sure some of them have potential. You can also participate in airdrops, so you can "invest" withot risking your money. I participatet in the Marinecoin Airdrop a few weeks ago Their Airdrop is still going on but they changed it a bit. You can now claim 20000 MTC every day as long as there are MTC left.I am pretty sure that it will become more profitable in the nearer future since it really has potential: a dev-less, community based coin with zero fees. It is time tested, is a machine to machine system and works with artificial intelligence. Can also become great with iot..
Join the discord group to talk about this project. : discordapp.com/invite/zpQyDu6 or telegram:  t.me/MarinecoinMTC

Marinecoin is going  to: Create a truly: self sustaining global actually usable and stable crypto currency by avoiding regulatory roadblocks. mtc distribution is a once in a lifetime opportunity.  This is a real community coin that is behing handed out by proof of promotion.  marineco.in -Right now they are holding an  absolutely free ICO and giving away the majority ofcoins for everyone,  This is a once in a lifetime opportunity- 20,000 coins for everyone who joins and does a simple task.Check it here: marineco.in/icoChances like this don’t come along very often.  A lot of the other top cryptos were once handed out for free.  Who knows what the future value for mtc will hold.  It could eventually make yourself a millionaire just by taking a few minutes of your time.