Disclaimer :: None of this is intended as advice, these are merely my thoughts!
Ethereum: Had 40x growth rate over the last two years. Ethereum is a decentralized platform that runs smart contracts: applications that run exactly as programmed without any possibility of downtime, censorship, fraud or third party interference.
Antshares (ANS) Smart assets & application platform based in China. C#, DPOS Ethereum, a partnership with Alibaba and KYC compliant, connected to major exchanges.
Factom: A blockchain-based system that’s optimized to store millions of realtime records with a single hash. Factom allows companies to create immutable database.
Factom store information in their own blockchain and then create a hash of that data and stores it into the Bitcoin blockchain. They are also working on adding that hash into ethereum and other big blockchain to add protection.
Siacoin: Distributed data storage. An alternative to Box, Google Drive. The big corporations would not have any access to your data in this point.
Augur: It is coined as a “prediction market” but basically, this means gambling. And gambling is big big business. Throw in the fact that the supply is limited at 11 000 000 tokens now and always and you can see the potential.
Stratis: Stratis is essentially doing something very similar to what Ethereum is doing - smart contracts. The primary difference being that the programming language for smart contracts will be C# and .net platform integration. Besides for that a java and javascript API will also become available Q4 this year. Stratis is also PoS and segwit ready.
Maidsafe has been around for quite a while now. 10 years exactly and they finally launch their Alpha MVP this week. Maidsafe is a decentralized database.
Instead of storing data on your computer, with maidsafe you can encrypt and upload it on the decentralised server. That way no one person can access your data without your permission. It is 100% secure and it doesnt use any space.
STEEM: A decentralized platform which allows to reward content creators easily.
Golem: Built on top of the Ethereum blockchain Golem is on track to becoming the world’s most powerful decentralised supercomputer, processing anything from scientific research in academia through to rendering the latest block buster movies.
NEM (XEM) NEM is the first private/public blockchain combination. It's one of the most popular Japanese based blockchains.
Waves (WAVES): Crypto-platform for asset/custom token issuance, transfer and trading on blockchain.
And many more … I will update this answer from time to time to add more of those :).