The high-denomination octadrachm — or eight-drachma — coin was struck by a little-known Thracian ruler named Mosses around 480 B.C., the time of the second failed Persian invasion of Greece.Coins of Mosses are indeed rare - see here - but ... the same scholar in some ways also argues for it having been found outside Greece (my bold).
Thessaloniki University professor of archaeology Michalis Tiverios said examples of Mosses’ currency are very rare.
“There are very few coins struck in his name,” Tiverios said. “Octadrachms were heavy coins used for transactions abroad, usually for mercenaries’ wages, which is why they are very rarely found in Greece.”
Swiss confiscation of rare Greek coin
Greece secures Swiss confiscation of rare ancient coin that was allegedly illegally excavated - The Washington Post: