It's an abbreviation of Duck, Duck, Goose. They don't really explain why they chose to name it after that game.

https://duck.co/help/company/name

Wikipedia provides

Weinberg explained the beginnings of the name with respect to the children's game duck, duck, goose. He said of the origin of the name: "Really it just popped in my head one day and I just liked it. It is certainly influenced/derived from duck duck goose, but other than that there is no relation, e.g., a metaphor."

My guess would be from the child's game "duck duck goose".

Maybe the creator really enjoyed that game as kid!