Although NiceHash is usually regarded as a mining service, it's better to say that it's a kind of a platform for selling/buying cloud mining contracts. What is special about NiceHash is that users can opt for both selling and buying the hash power on this platform.
F2pool is a Chinese multicurrency mining pool founded in 2013. Now it has servers located in the USA, Canada, Russia, Singapore, and several other countries. The pool has a big number of supported coins. Currently, it is possible to mine around 40 currencies on F2pool.
Icemining is an Ethereum and Sumokoin mining pool. Users can mine ETH and SUMO for a 1% and 1.5% fee respectively and through a Prop payment system. The minimum payout is 0.5 ETH and 2 SUMO.