Here’s a tutorial that I made a while back about making a chainmaille dice bag. The first half of the video is about making your own links from scratch, so feel free to skip ahead if you already have some links.
As for the links I used for this project, they’re 16 gauge (US gauge) galvanized steel with an ID (internal diameter) of 5/16 of an inch. Admittedly, the wire is closer to 14 gauge, but the manufacturer lists it as 16. I have a lovely rant about wire gauge consistency planned for the future.