Caucasus Celts, Silk Root Celts, Crimean Celts
I was thinking about that, if the Galatians survive longer then in our timeline, maybe they are just more unified and keep the Romans from ever making it to Anatolia. Likely making friends with the Sassanids and later Parthian Empire.
Celtic influence survives in Anatolia, these Celts are going to travel around so likely after the fall of the Roman Empire with no Byziunium to keep the Roman legacy standing Anatolia is a lot more Celtic, these Celts then travel north through the Caucuses and into Crimea. They will likely at first closely identify with their Galatian homeland but over the decades break away forming Crimean Celts and Caucasian Celts.
Now with the Celts, the question always come how will they effect their new neighbors?
Crimean Celts, I would think would be the most nomadic of the Celtic people, and the Caucasian Celts would pretty much blend into the Hellenized Caucasian people of the Caucasian mountains. Maybe forming a small monarchy but nothing big.
If these Celts survive, especially the Galatians, then you will have Celts on the Silk Road into East Asia. If enough migrate and trade you could have Celtic influences in East Asia today.