Settlers of Catan + Cities and Knights + Expansion Pack + House Rules = Complicated. To help mitigate the chaos we keep our settlements, cities, roads, and knights in tidy 3D printed hex-boxes:
The boxes have snap-fit lids with a slot to help with opening. We 3D printed a lot of boxes, to hold our standard Catan pieces, our Extra Catan pPieces, our 3D Catan Numbers, and some extra bits and pieces we use for our House Rules. The bowls are designed to be the same size as the land hex tiles in the game, for maximum matchy-ness.
The closed hex-bowls fit sideways in the Catan box, together with our Catan Card Holders, to keep things organized in one box so we can set up quickly when we want to play.
These bowls were designed in Fusion 360. To get started using Fusion 360, check out our article Tutorial Tuesday 15: First Steps with 3D Design Software Fusion 360. Or, if you just want to print these same 3D models, you can download the 3D-printable STL files from Thingiverse. Have fun, and best of luck against the barbarians and robbers!