pair (two of the same or similar items that go together); couple (two of the same or similar items); two equal non-collinear forces; that is a force couple in Newtonian mechanics; peer (somebody who is, or something that is, at a level equal); some, a few
for, to (expressing a recipient); to, in order to, so, for (expressing the intended purpose of an action); by, due, due on, due by (expressing a deadline); for (expressing contrast from what is expected); for, to, in one's opinion, as far as one is concerned (expressing an opinion, perception or perspective)