To avoid clutter, the initial theme_ substring is omitted from all themeable functions listed below.

WARNING: at the moment, this is only the list of themeable functions defined by product.module. It will be expanded as soon as I read the code of the other modules, so it is by no means exhaustive (yet).

function theme_<something> Module Notes
node_product product Render product node. Also used for pseudo-products
product_ac_product product Autocomplete product
product_price product Format product price info
product_view_collection product Default view for q=product. Might not remain stable according to comments
product_<ptype>_view auction
coupon
donate
parcel
Used in theme_node_product to apply product-type specific themes