Miners

Source: https://witnet.io/about

As with most blockchain structures, miners are nodes in charge of adding blocks to the blockchain. These nodes are selected by the Proof of Eligibility. Due to the Reputation system, the barriers to entry are lower than in other Oracles since new nodes do not need to stake a significant monetary amount, nor invest in expensive hardware to become eligible to resolve data requests or mining. This fact incentives new nodes to join the network and thus encourages decentralization.