Here are some of the promising ones imo:

#1 SunExchange - Get solar cells and lease them to schools and businesses in the sunniest places on Africa. https://thesunexchange.com/
#2 AsuraCoin - ESports betting platform which utilizes Smart Contracts for betting rules, odds calculation and results execution. https://asuracoin.io/
#3 Dfinity - Blockchain decentralized supercomputer cloud IaaS playform. Think of it as supercharged Ethereum network, with advanced IT capability. https://dfinity.org/
#4 Compound - Crypto lending platform that let users earn interest, just like how bank interest works. http://compoundcoin.org/
#5 Augur - Decentralized prediction market. Similar to betting, just that you are betting for real world events. The founder is only 22 years of old! https://www.augur.net/

Can't think of any on top of my head, not sure if I missed out any other interesting project.