I know there are ways, I'm just not exactly sure what they are. Anyone out there know?

Magical Keepsake box in the Mc for 150k 1-3 spaces.

The Multi-compartment box in the Cash shop for 500csc 10-15 spaces.

Other than that there's the random event/pet zappers.

There's random events that increase it 1 size or you can use Magical Keepsake Boxes (MC item) 1-3 spots.

There's also a Compartment Keepsake Box in the Cash Shop which I believe gives 10+ spots.

Thanks guys!