I was researching ancient Celtic coins and found a great site by John Hooker & Carin Perron. Through this website you have access to over 28,000 records and images of Celtic coins as indexed at the Oxford Institute of Archeology.
Why am I researching this? It is because the characters in my book use coins. I want to be as accurate as possible regarding the coins, and this site is a starting off point.
They even have animated “morphing” coins that show a Greek coin morphing into a Celtic one to show the similarity and highlight the differences. Below is the Greek one and the Celtic one they think was based on it.
Very fascinating! Based on just this one coin, I’d say the Celts were very creative. Go to the site and see the animated morph yourself. It is worth it!