Magnets!
I backed a previous campaign, and this is their seventh KS.
"This new storage and organization system can grow as you make your way through this wonderful Hobby of Miniature Painting. The Cobalt Keep Hobby Rack system can be used in single racks or expanded with multiple racks to fit your needs. The removable Paint Benches enable you to store your paint away from your desk, while keeping it easily accessible and transportable. Magnets in the Paint Benches keep your paints in place as you shift the Hobby Rack from place to place.
Video shows more, but I took a screenshot with the magnets!
4-slot insert: Pots and wide droppers
5-slot insert: Droppers
Freebies and SG's: Dunno about the dice, but freebies include a paint hilt and magnetic bases, as well as a wall mount.
https://www.kickstarter.com/projects/cobaltkeep/expandable-hobby-and-paint-rack-with-modular-shelves