Stepanov and Musser were working on generic programming in the 80s[0][1], which predates Haskell. I suspect parametric polymorphism was common in the FP world by that time, but I don't know whether it was used as an organising principle to the extent that Stepanov promotes.

[0] https://en.wikipedia.org/wiki/Alexander_Stepanov

[1] https://en.wikipedia.org/wiki/David_Musser