The Ego Stone (or Ego Gem) is the seventh Infinity Stone, hidden in an unknown realm known as the Ultraverse in the Marvel Comics Universe. Infinity War explains the Infinity Stones were created by the Big Bang that gave birth to the universe.

What could be a 7th Infinity Stone?

In the Marvel Cinematic Universe, the Infinity Gems are referred to as the Infinity Stones, which are the Space Stone, the Reality Stone, the Power Stone, the Mind Stone, the Time Stone, and the Soul Stone.

What is the 7th and 8th Infinity Stones?

So there are a seventh and eighth stones in 1610. I'm reading the seventh stone is called the ego Stone and the eighth stone is called the Rhythm Stone but I literally cannot find any of sources other than the Ultraverse ego stone.