Nebulos

In the Marvel G1 comic continuity, a planet of humanoids that had lived without war for thousands of years. A group of Autobots led by Fortress Maximus sought to relocate to Nebulos in order to escape their own millenia-old conflict on Cybertron, but their arrival created dissension and mistrust within the Nebulan community. The arrival of a group of Decepticons led by Scorponok soon afterward only escalated these tensions, and Nebulos' age of peace was lost as citizens binary-bonded to Transformers on both sides of the conflict to become Headmasters and Targetmasters.

Realizing the damage that was being done to Nebulos' once-peaceful culture, the Autobots abandoned the planet to join Transformers already on the planet Earth, believing (correctly) that the Decepticons would pursue them off-Nebulos.

After this the citizens of Nebulos tainted their own energy sources so as to be poisonous to any Transformers that might seek to return to their world. When Decepticons Darkwing and Dreadwind arrived soon after the departure of the other Transformers, they soon found themselves victim of this poisoning, and lay dormant for a time. They were later revived by Nebulan traitors Hi-Test and Throttle, who had stolen power-conversion plans that eventually created the Powermasters. Hi-Q, the creator of this process, eventually binary-bonded with a reborn Optimus Prime, and several of his staff joined with other Autobots, in order to combat the threat posed by Darkwing and Dreadwind. They, too, eventually left Nebulos to join the other Transformers on Earth.

From Teletraan I: The Transformers Wiki, a Wikia wiki.