Monkey shrimp or saron shrimp are usually reef safe.
But just like any scavenger shrimp, there would be few that would develop a taste for corals and invertebrates.
I have had a saron shrimp in my old tank for over 3 years and the corals did not have any issues with it.
The only problem I had with it is that I could never ever see the darn thing. It sits still on a rock and it becomes invisible.
It will stand its ground against a coral banded shrimp or arrow crab (sometimes to its detriment) so watch out for other aggressors in the tank.