Monero, the dark Bitcoin twin

Yes. They are legal in most countries, but there is a risk that they'll be banned in the future.

Its characteristics are stealth addresses, ring signatures, zero-knowledge proofs (zk-proofs), and RingCT form Monero's proprietary privacy protocol. There is no evidence yet that any transaction has ever been tracked and traced. However, certain governments and contractors are trying to develop tools to help tracing Monero. The future is uncertain and new tools might be used for old transactions. 

Monero is the top privacy coin. Monero is what Bitcoin noobs thought they bought. While not being in the past the best store of value, its strength lies in its payment function.