Items

Items are one use, so try to use them only/mostly in combat. In most occasions one of the members of your party will have a similar skill that provides the same effect.

Goos
They can be obtained from certain types of slimes (like those that have overridden the Merchant Camp or bought in some shops). They are equivalent to some potions, but slightly more expensive.

Food and Beverages
You can buy a bunch of alcoholic beverages that have no positive effects and just gets the Party Member that uses them drunk, but Simon can't get drunk so both Mana an Lust wines are useful on him. Here will only be listed those who give some sort of positive effect.