Depends how much risk you are prepared to take. If you want to play safe, Bitcoin, Ethereum and Litecoin are your friends. But don't expect to get rich in a few weeks.
If you feel lucky and don't want to miss opportunity with growing coins, you can try DeepOnion (has been growing consistently for the last 3 weeks) and YOYOW (new Chinese blog that pays for good content, similar to Steem).
It's exactly this , people should know whether they want a high risk and potentially high reward plan or they just want to take the slow and secure road . Bitcoin/Eth/LTC are certainly on that secure road because it's coins that either keep constant value or just increase , even if they go down a bit they get pumped up very soon after . Especially Eth because it has lately received a huge pump and gained 300$ per coin of value which is kinda insane when looking to the slow rhythm that Eth has been going with all these past years .
In another point of vue , there are lots of promising new coins that don't like any shitty coins that are derived from shitty projects that were just made to make their owners a bit richer (and there's really a shit load of those coins ) , there are coins with a real road map , a real utility and they are really bringing something new to the table , thus making people believe and invest in them . Bitcoin is an example of a way to get richer , but bitcoin was a monopoly and now is sharing the cryptocurrencies scene with 1000+ other currencies ! So it's your time to take action , believe enough in one of them to put some money in it and just hope that the bitcoin scenario repeats itself with that coin , it has been done already once so why wouldn't it happen again ?