Nxt is a blockchain platform developed by Jelurida, which is also developing the Ardor blockchain. Nxt's goal is to improve upon existing blockchain platforms with a modular toolset that enables users to create their own digital assets that can be listed on decentralized marketplaces. Nxt also features community driven voting mechanisms and has an architecture that separates the blockchain into parent and child blockchains.
The network is powered by the NXT token and has a Proof-of-Stake (PoS) consensus mechanism.

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.

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.