For now there are some experimental things in the exp module. See the maps and slices packages there. But yes, my understanding is also that they kind of waiting to see how generics work out. They've promised to make no breaking changes to Go v1, so adding any functions to the standard library is not to be taken lightly.

https://pkg.go.dev/golang.org/x/exp#section-readme

I think almost everyone is waiting to see those idiom too (myself included). If I'm going to rewrite stuff, I want to be able to justify it (less LOC may be be enough) and "do it right". Hopefully I get to see them in the sdlib soon!