I/O Coin cryptocurrency enables up to 1MB doc AES256 encrypted storage (and transfer), encrypted messaging, private payments and identities. The blockchain is dapps ready via api. It offers up to 15 second POS blocks at 4MB per block.
Stealthcoin (XST) has been rebranded to Stealth (XST): https://twitter.com/stealthsend/status/993226001101545473 Stealthcoin provides a complete anonymity solution for cryptocurrencies. Stealthcoin has a fair distribution with nearly four hours of low block rewards, a small premine of 1%, and the long-term energy efficiency of proof-of-stake minting.