I like polynomial and power series set notation.
K[X] (polynomial set)
K[[X]] (commutative formal power series set)
So, a super polynomial
"This is not even my final form."
K⟨⟨X⟩⟩ (formal power series set)
Even less limited
"And this... is to go even further beyond!"
@jmw150 If K(X) is the division ring, would that make K((X)) the formal power series division ring ?