Eight years ago I came up with the idea for ship add-ons that provide one's craft with extra abilities, and specified them further three years later. Two of them, the Submerger and Repeller are now functional. The first allows the player to briefly dive beneath the grid surface, where you'll be safe from enemies and their projectiles. The second will push away nearby Razors, Seekers and other players.
For now all ships are equipped with these add-ons from the start, but I also intend to implement purchasing them (with points) in the lobby, between flights. By then they should be visible on the ships as modules. Icons indicating their recharge progress are also not yet implemented.
The other two add-ons in the works are Depth Charges and a Ram.