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.