Mastering Ethereum: Building Smart Contracts and DApps by Andreas M. Antonopoulos
https://www.amazon.com/Mastering-Ethereum-Building-Smart-Contracts/dp/1491971940

How does Ethereum work, anyway? — how it functions at a technical level, without complex math by Preethi Kasireddy
https://medium.com/@preethikasireddy/how-does-ethereum-work-anyway-22d1df506369

Ethereum smart contract best practices by ConsenSys Diligence
https://consensys.github.io/smart-contract-best-practices/

Basic terminology for Ethereum — from gas to dapps (distributed apps) by Matt Condon
https://medium.com/@mattcondon/getting-up-to-speed-on-ethereum-63ed28821bbe

CryptoZombies is a free, interactive code school that teaches you to build games on Ethereum.
https://cryptozombies.io/

How to code your own cryptokitties style game on Ethereum by James Martin Duffy
https://medium.com/loom-network/how-to-code-your-own-cryptokitties-style-game-on-ethereum-7c8ac86a4eb3

The hitchhiker’s guide to smart contracts in Ethereum by Manuel Araoz
https://blog.zeppelin.solutions/the-hitchhikers-guide-to-smart-contracts-in-ethereum-848f08001f05