For example, priests who would wander out and gather resources like peasants, but return to the temple instead where the resources would be immediately converted into favor.
Or even a more barbaric Civ that gathers resources from battlefields in addition to other sources. Each human unit could be worth 100 food or something. Even some way of converting the 'armor' into gold, or some ratio based on cost of the unit... Some way of using corpses as a resource. Say a 100 food 50 gold unit would be salvageable for a while as a 50 food 25 gold instant resource, the peasant or whatever could drag the corpse back to a special building that would turn it into said resources.
Like I said, it'd probably turn the game it was featured in into some rating above PG, but it'd add an interesting dimension to gameplay, that's for sure. Especially if it was only one civ that could do it.