Helmet punched decoration references?

[Tarbicus]

I'm looking to pimp a Gallic helmet with punched decoration, as seen on the Gallic C in Zagreb Museum. Does anyone know of anything published on the subject with images of the patterns and motifs used? I imagine acanthus leaves and the like, but I can't find anything. Or should I just look to flora patterns on belt plates and fittings for hints and a feel of the style?

I really don't want gods or mythological figures as I want it to have an earthy and agrarian feel.

Ta.