The first blessing of birkat hamazon concludes with the statement that God prepares sustenance for "all of his creations that he created". What is the explanation for this double, redundant sounding language?
The point is that I don't think the phrase is redundant, but rather, a form of acknowledgement, here. I.e., we know that there are creatures and many living things, but we are acknowledging that G-d has created them.
Meir Friedman in Beis Talmud vol. 5 (page 354), after discussing variant versions which either leave out "which He created" or add "which He created in His mercy and in his Great kindness" (ברחמיו וברוב חסידיו) or leave out the whole phrase, gives two possible explanations:
1) He prepares for every species that he created the sustenance which is most appropriate and best for it.
2) Because he created them he provides all their needs.