Map is a pretty fundamental thing you might want to do to your data structures (and more). Look up all the places that Haskell's "Functor" pops up for example.
Filter is much more limited in where it's applicable, that's true.
In any case, I already gave another example in my comment: sorting. And sorting's API is done terribly in the Go standard libraries.
The Go standard library does a lot with callbacks; and yes, it manages to get something useful out of them via something even uglier: mutation.