I had the same problem, I was painting up a Pagan Peoples SAGA Warband, and could get some illustrations from Osprey Books, these are few and far between, internet searches on google do not produce much.
The old WRG Armies of Feudal Europe, gives a line drawing, but states that the Warriors are armed the same as the Prussians, but due to raiding may have had more armour and helmets, same fur waistcoats, white or bleached clothing, beards but with short hair.
They also carried the small almond/kite shield as the Prussians.
Thats about all I could find, I used Black Tree Germans as Warriors and a mix of Victix Vikings and Fireforge
Russians for Heathguard.
Steve M