Though most of the alts presently are just pump and dump coins and present a great threat, some coins are great potential coins.
Ethereum, Litecoin, Monero in my view have good prospects. Ethereum is the most widely accepted alt in the financial market and possess a good market capital as well. Litecoin has shown great acceleration in its market capital since adoption by coinbase and is a good option for a long term investment. Monero is the best privacy coin out there making it the best choice for making transactions throughout all the coins leading to it having a bright future.