Decred is an open source, hybridly mined and community managed blockchain. Developers can submit improvements to the network and receive DCR (Decred’s currency) as a reward if their suggestions are approved by the community. The mining protocol is based on a Proof of Work (PoW) scheme but every mined block includes five randomly selected Proof of Stake (PoS) tickets from the PoS ticket pool which vote on the validity of the previously mined block, whose miner will receive the mining reward only if the block is approved by at least 3 of the 5 tickets. The system seems well-designed and explains how the underlying probability distribution and constraints avoid that even entities with a very large amount of DCR can manipulate the voting in their favor. 1
Decred was forked from btcd which is a GoLang implementation of Bitcoin and then modified for the mixed PoW/PoS consensus. It does not offer native support for versatile scripting (read: smart contracts) and custom asset creation. With regard to the content blockchain project, Decred probably offers an interesting take on the consensus algorithm and on project governance.