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.

Holo is a decentralized hosting provider that is built on top of Holochain. DApps can be set up and deployed with Holo hosting, as a decentralized alternative to Amazon Web Services, or other centralized hosting solutions.
Holochain is a protocol for creating decentralized Apps and is different from blockchain protocols in several ways. The main difference being that Holochain takes an agent-centric approach to their consensus mechanism, and has a different approach to validating value transfers.
The HOT token is used for paying for hosting services on Holo, and users can be paid for offering their computing resources.

Hydrogen is a fintech company that develops API' for creating financial applications. They are developing the open-source Hydro blockchain platform that emphasizes identity management and security. The network is powered by the Ethereum-based HYDRO token.