Thanks, those all seem useful.
Assuming I'm following you correctly, Raku already has equivalents to each of those built in: we have code blocks[0], List.map[1] (or `for list -> $el { [codeblock]}`[2] which is a `for` loop, but not a C-style one), and the Iterable/Iterator Roles[3].
So I don't think those features give me any ideas for items to add to the library – but I agree that I'd be sad in a language without them!
[0]: https://docs.raku.org/language/control#index-entry-control_f...
[1]: https://docs.raku.org/routine/map