The Mason Bag

American masons carry their tools in a mason bag, sized by the overall length, like 20 inches. The best mason bags are canvas with leather handles, straps, and bottom, and cheaper ones are all canvas. Originally the fabric was linen and now it's heavy cotton. Compared with a box, a bag easily holds trowels and tools of assorted sizes and shapes and allows moisture to evaporate, which a wood or metal toolbox would not do.

Companies making or selling traditional mason bags in the US include Custom LeatherCraft (CLC), Genau Gear, Heritage Leather, Klein Tools, Kraft Tool, and McGuire Nicholas. Here are 2 links:
Heritage Leather Co. Tool Bags
Klein Tools - Canvas Tool Bags