I think the best altcoins of 2018 will be TRX, EOS, ADA, XLM.

At the time of writing here is the performance ytd for each coin (at time of writing)

• $TRX- +948%
• $XLM- +780%
• $EOS- +400%
• $ADA- +230%

These are amongst the alt coins that have performed the best thus far and will continue to grow through 2019. Personally, I am most excited for ADA. TMT was the first ICO on ADA by the way