Dragon Quest Heroes won't fit without adding a microSD card.
Over on its Japanese website (translated by IGN) Nintendo revealed the digital download sizes for several upcoming Switch games, and one in particular won't fit without the addition of a microSD card.
While the Switch comes with 32GB of memory, 6.1 of that is reserved for the operating system and other software, so Dragon Quest Heroes 1 & 2, which requires 32GB of space, won't fit without adding in a microSD card. As previously announced, The Legend of Zelda: Breath of the Wild will require 13.4GB of space.
Here are some others, all requiring less space:
Mario Kart 8 Deluxe - 7GB
Puyo Puyo Tetris - 1.09GB
Disgaea 5 - 5.92GB
Snipperclips: Cut it Out, Together! - 1.60GB
I Am Setsuna - 1.4GB
Nobunaga's Ambition - 5GB
Luckily, buying any game physically means you won't have to worry about file sizes, as the Switch doesn't require games to be downloaded from a physical copy.