The Matic Network is a sidechain based scaling solution for public blockchains. Matic aims to allow developers to better scale their Ethereum DApps by using a version of Plasma, along with side chains that use a PoS consensus mechanism. Matic plans on supporting other blockchains as well in order to facilitate interoperability.

ARK, which is a fork of Lisk, is developing an interconnected blockchain ecosystem that will make it easier for users to develop their own blockchains. Ark emphasizes interoperability and usability. Their moto is “Point.Click.Blockchain” and their goal is to allow for easy deployment of DApps. Ark's "push button blockchains" can be easily created with minimal programming knowledge. Ark also hopes to encourage adoption by developers by accommodating 18 different programming languages.
Ark has a delegated Proof-of-Stake (dPoS) consensus mechanism. Their governance model allows users to vote for delegates that secure the network. The top 51 delegates voluntarily share there tokens with their voters.
Ark contract execution service (ACES) connects ARK with other blockchains and will enable exchanges of value between them.

ProximaX is developing a NEM-based platform with several on-chain and off-chain protocols. At its core, ProximaX is based on the NEM blockchain, and is designed to be an all-in-one platform for developing DApps. The platform has several parallel layers that are intended to provide decentralized storage, messaging, streaming, and content delivery services. The network is powered by the NEM-based XPX token. ProximaX intends on using a hybrid consensus mechanism for validating value transfers on these layers. Consensus will be driven with a combination of Proof-of-Importance (PoI), Proof-of-Storage (PoSt), and Proof-of-Bandwidth (PoB).