RigPool is a Bitcoin mining pool that pays miners through a PPLNS payment system. The pool has a 0% fee and the minimum payout is made when the user reaches 0.001 BTC.
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.
FlyHodler is a cloud mining services provider. With HODL contracts, the users can withdraw all its initial investment, plus mining income. It works as a bank deposit, so the users can top-up and withdraw their deposits, and their hashrate changes accordingly.
KomodoPool is a mining pool for Komodo (KMD). The user can mine KMD through a Prop payment system with a 0% fee. The pool shares the transaction fees with miners.