Viacoin is a Script-based cryptocurrency derived from Bitcoin. Similar to Bitcoin and other cryptocurrencies, Viacoin is also an open-source project. Viacoin aims to be the cryptocurrency of future, by integrating many innovative key technologies such as SegWit, APoW, Lightning Network, Dark Gravity Wave, and more. Viacoin claims to allow 25 times faster transactions than Bitcoin. It can be merged mined with the other Script cryptocurrencies like Litecoin, This is done by using an Auxiliary Proof-of-Work (AuxPoW) algorithm. Every six months, Viacoin halves the block reward that is given to users for Viacoin mining, resulting in a low inflation rate of Viacoin. Check out CoinBureau for the complete review of Viacoin.
Gapcoin is a new prime number based p2p cryptocurrency, which tries to eliminate the sticking points of other scientific currencies like Primecoin or Riecoin. It's a fork of Satoshi Nakamotos Bitcoin, a decentralized payment system which is independent of banks, governments and other centralized regulators. With Gapcoin, you will be able to anonymously send money around the globe in no time. The big improvement in comparison to Bitcoin is that instead of burning electricity for its own sake, Gapcoins Proof of Work function actually does useful work by searching for large prime gaps