Waves: Decentralized exchange and crowdfunding platform. Lets companies and projects to issue and manage their own digital coin tokens to raise money.
Monero: Currently most popular privacy coin, though with a very high market cap. Since their privacy is all on chain, all prior transactions would be deanonymized if their protocol is ever cracked. This requires a quantum computing attack though. PIVX is better in that regard.
Zcash: A decentralized and open-source cryptocurrency that hide the sender, recipient, and value of transactions. Offers users the option to make transactions public later for auditing. Decent privacy coin, though no default privacy
Zcash is really very cool. Also, you can mine it successfully. I also offer you to pay attention to Litecoin and DASH. As for the cheaper alts these are KickCoin, TRON, Credits, Gladius, Stellar, and Cardano.