Beam is developing a confidential cryptocurrency that uses the Mimblewimble protocol. It will have a Proof-of-Work (PoW) consensus mechanism, and will enable private transactions that can be audited for compliance purposes.

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.

Bytecoin is a privacy focused blockchain that aims to be completely anonymous. It is the first digital currency based on CryptoNote technology and uses ring signatures. Bytecoin utilizes one-time addresses and multi-signatures to enhance security. Bytecoin has high transaction speeds and users are in complete control their personal information. Any identifiable details can only be seen if you allow it. Bytecoin, and CryptoNote, have led to several popular forks. Monero and Dash are both Bytecoin forks. The CryptoNote Proof-of-Work (PoW) algorithm was designed to provide ASIC resistance and enables anyone with a personal computer to mine it.