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.

Ignis is a blockchain platform that is being developed by Jeluirda; the company behind Ardor and Nxt. Ignis is a child chain of the Nxt blockchain. Jelurida is developing blockchain platforms that will enable users to develop decentralized applications, and will be based on a parent and child chain architecture.
Ignis allows users to create child chains with specific features and to create tokens that meet their needs. This project is closely related to Ardor and Nxt.

IOST (Internet of Services Token) is a blockchain platform that is focused on improving transaction speed and scalability. IOST has a unique Proof of Believability consensus mechanism that is based on past contributions and behavior.
The company claims that their platform will increase security and efficiency compared to other platforms. IOST uses a sharding technique that splits the network into smaller ones and randomly assigns tasks for the nodes on the network.