Some new information has come out about some Switch games. Specifically this is about how much space they will take up if and when they are purchased digitally.
1, 2 Switch will require 1.3GB,The Legend of Zelda: Breath of the Wild will require 13.4GB and Snipperclips: Cut it out Together will only require 1GB. Shovel Knight Treasure Trove is the smallest as it will 0nly take up 147 MB once fully installed on Switch.
Considering how fast these things add up, it might be best to purchase a MicroSD card to allow yourself store more data for game downloads.