Hello, I would like to post a suggestion I came up with here. I think its better here.

My first idea would be more combine themed furniture, walls and floors. Like the citadel floor or walls. Maybe also some health chargers and stuff.

The second idea would be like medical conditions and improvements via implants. Like you would be able to disable the food need for combine soldiers with an implantat. Or laser eyes, that make stalker colonists work faster.