Okay, some more suggestions:
A) Fleet suicide. I suggest this because it would be most gratuitous - could there be maybe an option for when you abandon a battle (through the Admit Defeat button or just by hitting Esc), for all your ships to immediately self-destruct? This would be as opposed to the current jump to the statistics screen. All your ships go kablooie, you get a Defeated! dialog box, continue as normal.
B) Explosive power plants. A new power plant type, perhaps a bit bigger and more productive than the standard Mk 3 generators, available for both frigates and cruisers. Its sole benefit is to increase (maybe double?) the damage the equipped ship does when it goes kaboom. I could see this as a popular module for “knife-fight” cruisers that are usually up in the enemy’s face anyway.
C) Footprint Magnification System. The FMS (also short for F@#$-Me Sign) launches one or two missile-sized objects that the enemy sees as ships of the same class as the one that fired them. Just like missile decoys but better. FMS drones can distract the enemy’s gunners - but not for long, since the drone won’t take a lot of damage before failing, allowing the illusionary “ship” to pop like a soap bubble. I see the FMS launcher working kind of like the Order Limpet Launcher (slow launch speed, maximum number of drones at once), only with the projectiles moving in among the enemy ships (for the graphic, maybe the drone surrounded by a circular halo about the size of a frigate or cruiser). Might be kind of tough to work out how this sucker gets shot at and hit though - don’t want one FMS sailing around for the whole combat because the enemy flat-out can’t hit a missile-sized object. That would be unbalanced.