Battles and/or story content that has you navigate your ship(s) through megastructures - things like hollowed out asteroids, megalithic artifical structures, ship graveyards, debris fields - potentially even within planets' atmospheres. The possibilities with it are endless, but the idea is to have battle/exploration gameplay with some static, fairly unique terrain on a bit more of an intimate scale. Some of these spaces could be too tight for larger ships to practically navigate. There could be recursive mission types that take you into these spaces, with rewards like weapons caches, blueprints, goods. Certain sizes might restrict the battles only to frigates, or severely reduced deployment points.
They'd basically be the equivalent of Mount & Blades' bandit hideouts - where you take a few of your best ships with you into a small-scale, close quarters fight. It'd be even better with a system like Starship Legends.