Some of my favorite are Litecoin, PAY, and ICON.
Litecoin is a fast and low fee currency that fulfills Bitcoin's functions better. A bit more centralized because Charlie Lee guides the direction but I'm like the way it's going.
PAY is the TenX token, Multi-crypto card that aims to make crypto spendable. Great communication with community and COMIT to scale in the future and banking licenses to supply even more customers.
ICON is the first Korean Blockchain/ICO. Backed by Multi-billion companies including, Dayli financial group, yello Mobile, and more. They already have partnerships with multiple universities, banks, securities, insurances, and more to come. Built on Loopchain, a separate blockchain than Bitcoin, I see immense potential in 2018 and forward.