Taking a look in descr_sm_resources gives me the following list:
gold - fine
silver - fine
pottery - did the ancients trade pottery?
furs - completely unused
grain - completely unused due to hardcoded side-effects
timber - no complains, though it doesn't seem to be present much in Gaul and Germania...
iron - fine
olive_oil - fine
wines - fine (the Romans liked their wine

)
slaves - present in every settlement for some strange hardcoded effect which takes place when a faction enslaves a region
glass - no complaints, except for the fact that it isn't very widespread at all and I don't get what determines which regions have it and which not
marble - no complaints, except for the fact that it isn't very widespread either - does anyone know where it should be found?
textiles - wouldn't each region produce its own textiles (not that I know much about it)? Or is this meant to be fancy clothes, in which case it should be renamed nad redistributed, because I somehow doubt the Britons exported fancy costumes

purple_dye - no complaints, but shouldn't it be widespread throughout the Punic regions?
incense - fine
silk - fine
wild_animals - used, but I have never heard of the ancient wild animals trade

hides - not sure what that's meant to represent either
tin - fine
copper - fine
lead - fine
amber - fine
elephants - not tradeable; used in EDB to mark out the recruitment of Numidian cavalry and elephants - can't hidden resources do the same?
camels - present in descr_regions but untreadeable and not used in EDB
pigs - completely unused
dogs - used as grain
Can't furs, elephants, camels and pigs at least (not sure about the others) be used for other resources? For instance, I can think of salt, Indian spices (to boost India trade-wise), and some other things I can't think of at the moment. My writing has to but cut short here as I have to go - but what do you think? Does anyone have any suggestions?
Edit: Maybe a horses resource?