I don't think any good altcoins have come out in 2015. Ethereum is the only one that will be coming out. Here are the ones I think have promise to do well in 2015:
Good possibilities:
TRIReason: Very low marketcap and has a couple of good devs. One is working on a trading app that you will need TRI to use.
RDD - it's mostly on
https://www.reddcointalk.org/ and somewhat on
http://www.reddit.com/r/reddcoin/Reason: Has somewhat decent distribution. Devs haven't given up on it in over a year and have more features planned - Browser wallet, etc.
SYSReason: Has decent devs and could be actually useful.
and obviously
EthereumAlso possibilities:
VNLReason: One of the very few coins that is not a fork of bitcoin. Claims to be VC backed. I'm not entirely sure where this one is going, but it's one to look out for.
SSDReason: Very low market cap anon coin. Uses steganography for anon. The dev is very good, but I'm not certain how often he's working on the coin.
BLKReason: Has somewhat decent distribution. Has decent devs that haven't given up.