What is a mining pool?
Mining pools are groups of cooperating miners who agree to share block rewards in proportion to their contributed mining hashing power.
While mining pools are desirable to the average miner as they smooth out rewards and make them more predictable, they unfortunately concentrate power to the mining pool’s owner.
Miners can, however, choose to redirect their hashing power to a different mining pool at anytime.
1.Ant Pool
I'm investing in this site too.This site mines about 15% of all blocks
2.F2 Pool
This site originally based on china,and this mines about 12%.Has been running for six months
3.Bitfury Pool
It's 12% too but you can't join this because it is private
4.BTCC
It's the third largest mining pool in china,it can be trust too.It's mines about 7%
5.Via BTC
It's a new mining pool that has run for 1 year
source-https://bitcoinworldwide.com/mining/pools/