Everything you ever wanted to know about rewards for staking Fetch.AI tokens:
https://medium.com/fetch-ai/staking-and-incentives-for-the-fetch-ai-ledger-40bf885871e7

If you are new to staking, head of research Jonathan Ward has written a second article giving a brief overview of the concept. He also explains why Fetch.AI is using Proof-of-Stake rather than Proof-of-Work:
https://medium.com/fetch-ai/fetch-ais-staking-model-explained-e9a987a89529