Celestials are an all-powerful race of galaxian titans who helped shape the Marvel Multiverse. Older than creation itself, their technology is the greatest apparatical find most any inquisitive mind can ascertain.
Technology out in the Universe
Many ancient celestials had visited other worlds long before the Earth came into being. One such world was that which belonged to an Elder of the Universe called Gara whose planet was made the home one such Celestial. He would introduce them to a device that would bestow upon them their greatest potential selves, but it would come at the cost of personal degradation. Gara's entire society destroying itself as a consequence of their newfound greatness.
Technology on Earth
The very first indication of Celestial technology found on Earth was in the primordial age when one of the alpha Celestials called The Progenitor fell on the newly forming planet and died there due to Horde affliction. It's hyper-cosmic fluids seeped into the prehistoric soup that would be the keystone of life on the face of the world several billion years down the line after space giants demise.
From there another of said Celestial's host would descend upon the planet and do battle with it's prehistoric defenders, from there the 1st host would respond and do battle with them but refused to dispatch of the Earth as they saw the potential leaving it to live.
After having soundly bested the Avengers of old, the Celestials would run some experiments on the native cro magnum race before departing towards the stars. Leaving behind some of their mechanical engineering to the two divine sapien tribes that were born of their evolutionary thesis finding.