Spectrecoin is a privacy-focused cryptocurrency with a Proof-of-Stake (PoS) consensus mechanism. Spectrecoin uses ring signatures, stealth addresses, and Tor to provide privacy and anonymity.

Grin Coin is a community driven blockchain project that aims to create a lightweight mimblewimble blockchain that will enable anonymous transactions. Grin has a Proof-of-Work consensus mechanism. Transactions are executed while hiding addresses and amounts.

Horizen, formerly called ZenCash, is a cryptocurrency focused on privacy. Horizen has an end-to-end-encryption system with zero-knowledge technology, that allows for anonymous transactions and messaging.
The company suffered a 51% attack in June, 2018 and has since re-branded as Horizen. Horizen hopes to combine anonymous transactions and messaging with an emphasis on community governance.