I had an idea to create space mines that I tried to implement myself, but it is now clear that I don't have the know-how to do so.
My idea was to create space mines by implementing two abilities from the original game: Deploy Squadron, and Self Destruct. A unit (it could be one that already exists, like the Escort Carrier) could deploy a squadron of a special fighter that would be unable to move, or be easily destroyed by enemy fire. Then when enemy ships got close enough, you could activate Self Destruct.
Just an idea, but one I liked. If anybody could help me with it I would appreciate it, or if the Mod team wanted to implement it, that would be even better.