RSK is an open source smart contract platform that is secured by the Bitcoin network. RSK is designed to add value and increase the functionality of the Bitcoin ecosystem by providing smart contracts that are compatible with the network's code and can be written in Solidity. RSK smart contracts are powered by the SmartBitcoin (RBTC) which is linked to Bitcoin. (1 RBTC=1 BTC)
RSK developed the RIF Token which is intended to enable users to access a range of DApps within their ecosystem. In September 2019, RSK purchased the Spanish social media platform Taringa with the goal of using the RIF token as an incentive to encourage users to share content.

The Aztec Protocol is an efficient zero-knowledge privacy protocol designed to enable private transactions on the Ethereum blocckhain. Their zero-knowledge proofs enable private transactions that can facilitate a variety of inter-operable financial applications on Ethereum. Aztec is a ConsenSys portfolio company.

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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.