I noticed there were plenty of designs for the full size Altoids tins, but hardly anything for the Smalls tins. In the process of working on an insert for my own use I decided to make an empty insert with locking tabs that can be easily remixed by anyone for their own purposes.

The insert is dimensionally accurate but not perfectly snug to account for potential variance in tins. It snaps in easily and the locking tabs hold it in place well. With a little bit of prying, the insert is also removable.