These days, there are nearly no Pro-only brush at all... let alone any worth mentioning. Last August, MAC moved the bulk of the Pro-exclusive brushes out to every freestanding store and took the "PRO" stamp off of them. Put them on the website, too!
The only Pro brush left that's awesome is the 174, which is a giant super-soft angled powder brush. It's also around $74... so not necessarily a must-have.
At a regular store (or on the website) there are a few former Pro brushes that rock... epecially the 222, 272, and 263. Those are among my must-haves. But they're not Pro-only anymore.