> and possibly other shells?
Years ago--I don't if it's still the case--but the fish shell used ^ to redirect stderr.
EDIT: I remembered right:
https://web.archive.org/web/20111111003423/http://fishshell....
but it seems it's no longer the case:
fish> echo foo ^ bar
foo ^ bar
https://fishshell.com/docs/current/tutorial.html#pipes-and-r...