Created from scrap by the out of control Creation Matrix on the planet of Junk.

They are nearly identical to each other, having only minor variations.
Junkions all have some level of Accelerated, Cloning, Enduring, Energon Synthesis, Facsimilating Spark, and Failsafe.

The Junkions appear to be led by Wreck-Gar, but their society is so loose and chaotic you have to take his word for it.
Wreck-Gar is often accompanied by Rum-Maj, who might be another Junkion government official, or Wreck-Gar's subordinate, or superior and actual ruler of Junk.

Other notable Junkions include: Ashtray, Detritus, Greasestain, HAZMAT, Junkyard, Re-Cycle, Rubbish, Scrapheap, Trashbin, and Wasteoid Gamma.

Allegedly an exploration team from Junk, lead by Clocker, encountered the Enigma of Combination.
Clocker and his teammates: Cannonspring, Chaindrive, Mainspring, and Pinion can supposedly gestalt combine to form Tempus Inimicus.