Salvaging
Combat leaves wrecks behind. Fit a salvager and you recover materials from the hulk after the fight.
Loot arrives in two layers. First, the defeated enemy drops directly from its loot table (tagged by difficulty tier). Second, the wreck itself can be recycled into raw and refined materials and the occasional component. Tougher wrecks yield richer salvage, so clearing high-difficulty encounters feeds your industry as well as your kill count.