Firstly, the classic turret. Next, you have 2 modes of ships. Offensive, which will chase off and shoot any enemies, returning to the ship it is following once it has killed its target. And a defensive mode, which means it will follow around its originating ship in a range of blocks you can set, and will shoot at enemies that come nearby, attempting to protect your ship at all costs. Then, missile/kamikaze, which requires thrusters, and will undock at the first sign of enemies, or if you set it to launch when you press a certain button, it will fire and follow either the currently locked target or act like a homing missile (whichever you set it to, and you can choose which factions it will or won't follow) and slam into the enemy (so if fitted with dis-integrators it can be devastating.