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.
FlyMining is a Scotland-based cloud mining service provider where users can start mining for as low as $10. It features monthly and lifetime contracts, the latter of which will only become obsolete once they are not profitable for the user. Users can pay for electricity fees with EUR/USD, rather then paying them from the mining revenue, allowing them to hold on to the entirety of their mined BTC. FlyMining features publicly accessible webcams and also allows users to confirm that their bitcoins are "freshly" mined through the block explorer. Contracts can go from 0.1TH/s to 60TH/s.
Based in Hong Kong, Hashfox is a cloud mining services provider. Bitcoin (BTC) cloud mining contracts are available on the platform with the possibility to pay either by using Cryptocurrencies or Fiat.