This mod fills most of the galaxy with the Grox. Some solar systems are still empty, though. Because these uninhabited systems are super-rare, all systems can now have up to 50 planets.
I decided to make a small story for this mod, here it is:
Originally, the galaxy was ruled by two great empires. The Traviar empire and the Grox empire. The Grox empire knew that they couldn't win a war against the Traviar, so they decided to become cyborgs to increase their melee strength and they started to use "Dronox" to attack others on T1+ planets. The cyborg Grox were much faster and stronger, allowing them to create bigger weapons of mass-destruction faster. Eventually, they managed to defeat the Traviar, gaining almost all of the galaxy. Only one Traviar was left alive: Steve, who had the Staff of Life. Steve fled to the Core, waiting for another empire to rise and stop the Grox.
Known issues: You must make a new galaxy before installing this mod.