Yes, ostriches have two-toed feet (most birds have four toes, some have three).
Another two-toed animal is of course the Two-toed Sloth (which has two toes on the forelimbs, three on the hind).
However, a better example of an animal with degenerate forelimbs is the Two-toed Amphiuma, a kind of aquatic salamander.
I believe there are other amphibians and reptiles that may have only two toes on some limbs. In these cases, the limbs are completely useless, and are in the process of being lost entirely. They don’t have much in the way of musculature or bone structure.
The odd thing about T. rex’s arms is that, although they were highly reduced, they were not degenerate in the sense of losing their musculature, joint structure, etc. They were apparently functional, in that they could be moved in the normal manner. What their function was (if any) is a mystery.