There's a free priest's collar at DAZ, but you really need Michael's shirt for it to work. There are also a few other props that go with it. It's under the archive section at DAZ. That probably doesn't help much in the way of robes.

Poser 2, 3, 4, 5, 6, 7, 8, 9, 10, Pro 2014, 11, 11 Pro