It's not always easy to predict which artists are going to have breakout years. Although some musicians have an undeniable "it factor," other acts come out of nowhere and have blockbuster success.

Months ago, when The Boot announced its list of 2018 Artists to Watch, our staff members suspected that more than a few rising stars would have solid years. However, as we survey the list in December, it's a pleasant surprise to see just how many musicians equaled -- if not surpassed -- our expectations.

For example, Colter Wall followed up his self-titled 2017 effort with a new LP, Songs of the Plains, that reached the Top 20 on the country charts. I'm With Her, meanwhile, put the "super" in "supergroup" and added a successful tour to a year that also included the release of a stellar full-length disc, See You Around.

Five artists on our original list really stood out from the pack, though, for their superlative years. In alphabetical order, they are ...