Most Anonymous Cryptocurrencies

Monero

It is so secure/anonymous and private that you can’t even see the amount transacted between the different parties. Even law enforcement people weren’t able to find how much Monero the Alphabay owner had at the time of shutdown.
Monero uses complex on-chain cryptographic methods such as Ring signatures, RingCT, Kovri, and Stealth addresses to protect the privacy of its users.
However, for a crypto like Monero, I think such super privacy is worth it and I am highly positive about its growth because the development guys of Monero are very well aware of their strengths and weaknesses.

Benefits of Monero Cryptocurrency:

1. Private: No one can see how much balance you have by looking at the blockchain.
2. Secure: Irreversible cryptographic math secures Monero transactions and wallets.
3. Untraceable: Monero coins can’t be traced back to the blockchain due to encryption.
4. Decentralized: All nodes or wallets are equally eligible to verify Monero coins.
5. Fungible: All coins have the same market value irrespective of time or place.

Zcash

Zcash uses a different approach to become truly anonymous.

Zcash works on a zk-SNARK protocol, also known as zero-knowledge proofs. To understand this protocol more, read here. Zcash, however, have not implemented it yet as a default which means they still have an open blockchain/ledger similar to Bitcoin.
But of course the research is underway to make it more feasible. Whenever it happens, Zcash will be good to go –To Da Moon! as we say in the cryptosphere.

Komodo

Komodo is the underdog in the cryptocurrency world, and also one many are unaware of. The interesting thing, however, is that they are also anonymous crypto.
Also, Komodo is not only for private transactions because they are much more focused on decentralized exchanges, cross chain atomic swaps etc. Hence, it is quite a decent project to look into.

Verge (XVG)

Verge has adopted a different approach as compared to others to become private and anonymous.
Unlike its many peers, it doesn’t use cryptography as much to become an anonymous cryptocurrency. Instead, they use Tor and I2P network to achieve their goals.
It is so because they believe that an open ledger is something that is required by the users to verify and see where their transactions are getting received/used. They also have some other unique features such as atomic swaps or fast transactions.

DASH

DASH is definitely one of the most popular and trailblazing cryptocurrency of 2017.
DASH’s privacy feature is basically in its simplest form a coin-mixing service performed by its master nodes and is proudly called PirvateSend. This form of privacy provides an analyzable meta-data to find out the real sender/receiver.
So, for now, I will keep DASH here on this list until the DASH team removes it from their official website but I wanted you to understand the whole perspective in a broader way.