Right now the most attractive one is DeepOnion. It is just unbelievable. Every week, (for legendary ranked members) they are giving away as much as $1,000 worth of coins. If you participate in all the 40 rounds, it means that you earn $40,000 without any work at all. And that particular currency is having a very high potential for price increase.
I signed there and didnt receive anything. Also used their wallet but it wont connect to their network.