Ubiq is an Ethereum fork that aims to create a more stable smart contract platform for building DApps. Ubiq's protocol currently uses a Proof-of-Work (PoW) consensus mechanism, but will switch to Proof-of-Stake in 2019. The network is powered by the UBQ coin.
Ubiq's goal is to create a reliable and stable platform for developing DApps by modifying Ethereum's code base with important changes that will make it more secure and reduce instability. Consensus is based on their Flux Difficulty Algorithm, which is designed to constantly adjust the hash rate to protect against network attacks.

The Elrond blockchain platform is designed to be a public development infrastructure that will be more secure, efficient, and scalable than other blockchain platforms. The Elrond blockchain is aimed at DApp developers and enterprises. Elrond will have a Prof of Stake consensus mechanism, and will include an Adaptive State Sharding feature that will allow multiple validators to process transactions in parallel.

T‍he Flow Blockchain aims to be a developer-friendly blockchain for a new generation of DApps and digital assets that power them. Flow Blockchain is based on a unique, multi-role architecture, and is designed to scale without sharding, so that it can accommodate consumer applications with more users. The project was created by Dapper Labs, which previously created Crypto Kitties, one of the most popular blockchain collectible projects. Flow is now being used by NBA Top Shot, an officially licensed NBA platform for player related, blockchan-based collectibles. The founders: Roham Gharegozlou, Dieter Shirley, and Mikhael Naayem launched Flow with the goal of simplifying the DApp development experience.
Flow uses a Proof of Stake consensus mechanism. Flow coins are intended to be used as payment for validation services, data and computation, governance, as well as for collateral for secondary tokens that may be created on the platform in the future.