Emily Rogers, a well known insider on ResetERA who correctly reported most of the Switch specs, hinted at Labo's reveal, and correctly warned us that 2018 would be a quieter, more port heavy year for Switch, is at it again. This time, regarding Nintendo's first party Switch lineup for 2019. In a post on ERA lamenting about the lack of small, eShop only games from Nintendo, Rogers simply replied "Stay tuned for next year. You will be pleasantly surprised".
Keep in mind this is a rumor, or vague tease if you will, and Rogers has gotten some things wrong before. But she seems very confident in this one.
Considering everything else she's gotten right about the Switch so far, it's safe to say 2019 will be the year more Snipperclips and Box Boy type games will come from Nintendo in 2019 for the Switch. I really like it when Nintendo puts out games like these, it provides a nice buffer between their big releases, so can't wait to see what will come of that.