Below are photos and drawings of the bone tablets found in Olbia, dating to the 5th cent. BC. It is believed that there were many followers of Orpheus in this area. They were found in a Soviet excavation in 1951, but not published until 1978. The scholarship on these tablets is still in its infancy. As of yet, no other tablets like these have been found.
Translation: Life death life Truth A (symbols like lightening bolts) Dio (i.e. Dionysos) Orphic
Translation: Peace war Truth falsehood Dio (lightening bolt symbol) A
The reverse (drawing on right) looks like it could be a flute or similar instrument. It also could be an offering tray. Other markings could be more lightening bolts, or perhaps they are the letters IAX meaning Iakkhos.
Translation: Dio (lightening bolt) Truth (unknown word) soul A
The reverse (right) may be a stool covered with a fleece, as used in many initiation and/or purification rituals.