Aeternity is a smart contract driven blockchain platform that aims to integrate real world data and improve the overall performance of smart contracts. Aeternity has a hybrid consensus algorithm that combines PoW for verifying transactions, and PoS for governance purposes. The platform is based on a system of state channels that allow users to interact privately with each other and record this information off-chain.

Tendermint is a consensus algorithm that was created by a company called All in Bits. The open source algorithm is Byzantine Fault-Tolerant and uses an authenticated encryption system to secure transactions. The Tendermint consensus mechanism was developed in 2014 for the Cosmos Network. The Interchain Foundation, which is developing the Cosmos Network, continues to employ All in Bits to support Cosmos.

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.