Privacy is good for crypto. These four coins hide transactions in different ways.
Zcash uses zk-SNARKs, which are very good, but they need a trusted setup, which is risky.
Pirate chain uses zk-SNARKs too, but for all transactions. It also uses Komodo, which is a fork of zcash.
Monero uses ring signatures and stealth addresses, which are different from zk-SNARKs. They also have bulletproofs, which make transactions smaller and cheaper. But they are less scalable and less anonymous than zk-SNARKs.
PRCY uses zk-SNARKs and bulletproofs, which is a new combination. It also has a feature called stealth staking, which lets you earn coins while staying private.
I don't know which one is best. You should learn more before you pick one.