Zcash (ZEC) is a cryptocurrency with strong cryptography that is supposed to provide high security and privacy. At some point, Zcash was endorsed by Edward Snowden and Roger Ver. Zcash is a Bitcoin fork and it exists since 2016. The mechanism providing privacy is called zero-knowledge proofs (or zk-SNARKS).
Particl (PART) privacy coin fuels the Particl ecosystem. You can buy the coin on the number of custodial and non-custodial exchanges alike. The fiat purchase with EUR is supported by the Litebit exchange.