Monero is a decentralized public ledger protocol whose focus is on increased privacy. It was created in 2014, with the goal of establishing a privacy focused blockchain that would allow users to send and receive transactions anonymously, and not pseudo-anonymously, like Bitcoin.
Monero uses an obfuscated public ledger that prevents anyone from determining the source, destination, or amount of payments. Unlike many other cryptocurrencies, payments and account balances on Monero remain entirely hidden. This is one reason that XMR, the Monero currency, has attracted some users that are involved with illicit activities.
Monero uses a Proof of Work consensus mechanism that requires less computing power from miners than Bitcoin does. Because of this, mining Monero has become an alternative source of revenue for some websites and apps. .

.

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.

DASH, or digital cash, is a leading anonymity-centric digital currency that was created as a fork of the Bitcoin protocol. DASH allows users to make anonymous transactions instantly with very low fees.
DASH uses a lighter hashing algorithm (X11) and has a block time of 2.5 minutes. This significantly increases transaction time compared to bitcoin. It also introduced a system based on "Masternodes" and "Instasends" that provide incentives to users for securing the network and contributes to making transactions faster.
Users invest 1,000 DASH to host a Masternode, and then receive 45% of the reward for every block that is mined. DASH was designed with a decentralized governance model and a sustainable funding system that allocates a percentage of each block for network development purposes.
Although, Dash has not been able to attract as many developers and financial institutions as other cryptocurrencies, it is well positioned to continue growing and innovating.