PIVX is a cryptocurrency that is focused on privacy, speed, and low transaction fees. It was originally called Darknet and was forked from DASH. PIVX has a strong focus on community governance.
PIVX (Private Instant Verified Transaction) uses a privacy-centric Proof-of-Stake consensus protocol that allows anonymous staking.

ZCash is a privacy focused cryptocurrency protocol that enables users to make transactions anonymously. Users to hide the sender, receiver, and amount of every transaction. ZCash has several high profile advisers and investors, including: Roger Ver, Gavin Andresen, and Vitalik Buterin.
ZCash has a fixed supply of 21 million coins; 20% of which will be allocated as a founders reward that is split between investors and developers. This founders reward has been the subject of controversy and has led to a fork of the ZCash protocol.

Bitcoin Private is a community-driven fork of the Bitcoin protocol. It is somewhat unique in that it was created as a result of a privacy-focused co-fork of Bitcoin and ZClassic. Coins were distributed on a 1:1 basis to BTC and ZCL holders. Bitcoin Private (BTCP) uses the same privacy technology as ZClassic (zk-snarks). Transactions are published on a public blockchain, but the sender, recipient and other transactional metadata remain anonymous. Bitcoin Private has a larger block size, and enables anonymous transactions that are more secure than the original Bitcoin protocol.