Ethereum classic, Cardano, Nano, IOTA, NEM, EOS, QTUM are of my list for 2019 altcoins favorites.
Why classic? Poor roadmap for 2019 and they did not implement all the things from 2018 roadmap. Dead coin
Apparently people buy coins, the holder is quite a long time, and there are no results. It seems to me that today you need to transform your portfolios and send your money to invest in more promising coins. I like ethereum, stellar and NEO.