Namecoin is a blockchain-based DNS that allows users to register domain names with a ".bit" domain. Namecoin was the first fork of the Bitcoin protocol and it aims to remove centralized control over domain registration. It was the first cryptocurrency to use Auxiliary Proof of Work (AuxPoW) as a consensus mechanism,
where a child blockchain is dependent on the Proof-of-Work consensus of the parent blockchain. This allows for Namecoin and Bitcoin to be mined simultaneously, and when a new block is created on Bitcoin, it will also be added to the Namecoin blockchain.
Namecoin is a very important project that represents one of the best use cases of blockchain technology in protecting free speech and resisting censorship on the internet. It is powered by the NMC coin. The decentralized DNS provides more security from hackers and government intervention.

Bytecent is developing a decentralized rewards network powered by blockchain. Bytecent allows merchants to create customer loyalty programs that are cross-site and cross-platform compatible. Consumers are not restricted to using their rewards with just one merchant, and can redeem them anywhere Bytecent is accepted. In addition to secure transactions and portability, Bytecent never expire and there are no limitations on how many Bytecent you can accumulate or spend. BYC can be converted to Bitcoin, cash, and gift cards. Bytecent uses a variation of Proof-of-Work (PoW) for consensus that requires miners to manually attend to their computers and is called Proof-of-Miner (PoM). It's designed to prevent the use of advanced and autonomous mining hardware. Avanquest Software, a leading developer of consumer software, has implemented Bytecent for their rewards program.

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.