Metadium is developing a blockchain protocol for Self-Sovereign Identity. Their goal is to allow users to own all aspects of their identity. Metadium's network is powered by the Ethereum-based META token.

SelfKey is developing a blockchain-based self-sovereign identity ecosystem. Their decentralized identity management solutions are designed to allow users to better control their personal information, while also facilitating KYC procedures for a variety of purposes. SelfKey's platform revolves around the concept of Proof Of Reputational Stake, which requires users to stake Ethereum-based KEY tokens to participate in the network. Smart contracts release the staked tokens when the user leaves the ecosystem

The Sovrin Foundation is a non-profit organization dedicated to establishing the Sovrin network. Their goal is to create a purpose-built blockchahin, with a native token, that will facilitate creating and maintaining self-sovereign identities. The Sovrin token will provide incentives to value exchange that preserves privacy. It could also enable a global marketplace for digital credentials and personal data.
This is an important project that has lofty goals, but has the potential to revolutionize several major industries.