Bitcoin, Ethereum
https://mastanbtc.github.io/blockchainnotes/consensustypes/
https://blockgeeks.com/guides/blockchain-consensus/
https://medium.com/@chrshmmmr/consensus-in-blockchain-systems-in-short-691fc7d1fefe
https://medium.com/@lyaffe/nxt-proof-of-stake-theory-vs-practice-e895ac8cb5bf
https://medium.com/@jb395official/an-introduction-to-qtum-proof-of-stake-mining-a-racing-story-f11a3f48009f
https://blog.cosmos.network/consensus-compare-casper-vs-tendermint-6df154ad56ae
https://blog.cosmos.network/consensus-compare-tendermint-bft-vs-eos-dpos-46c5bca7204b
https://www.hyperledger.org/wp-content/uploads/2017/08/Hyperledger_Arch_WG_Paper_1_Consensus.pdf