I’ve just read that the Romans had finger-rings that were also keys (or keys that were also finger-rings).
It seems wonderfully appropriate for the League, and more relevant now given the rules update about locks and keys and strongboxes.
See slide 4 of the section “The History of the Key” on slate.com/articles/arts/desi … more_.html
slate.com/content/dam/slides … key_04.jpg
Might not be too hard to make, for someone with suitable tools.