New to this thread, but I’ve seen three animals that could be considered rare: the Eastern Barred Bandicoot (was declared extinct in the wild in 2013, but has been reintroduced to mainland Australia successfully).
The Florida Scrub-Jay, of which only about 1000 remain:
And last weekend I got a chance to see the Brush-tailed Rock Wallaby; estimates put their population in the wild at ~100. The ones I saw are wild, but are safely living their best life in a preserve that’s protected from foxes by an electric fence. I haven’t finished processing those photos yet though.