I started dabbling in wood carving (mostly relief carving), but after a while I decided that clay relief carving was what I preferred. At the moment I use a mix of three clays ... air drying, apoxie and polymer. Each clay type has its own benefits, with the air drying clay being the most basic, but vulnerable to damage; apoxie needs no additional curing procedure other than time; and polymer clay being the most veratile, but needs to be 'cooked' in a conventional oven in order to cure.
I used Lime wood to carve my first pieces, and continued to use them as a base for my clay reliefs. However, the increasing cost of buying wood in the UK, lead me to experiment with MDF, which is proving successful so far. So far, when working in clay, I have based the pieces on vintage photographs discovered on Pinterest.