Mercedes Ruehl was on a recent episode of Life in Pieces, which also features Diane Wiest and Thomas Sadosky in the regular cast. Colin Hanks has done Broadway, too.
Gregory Jbara, Len Cariou and Tom Selleck are all on Blue Bloods as regular cast members. I've also seen Alice Ripley and Bebe Neuwirth on that show as well.
It's no longer on TV, but I'm watching 'Nurse Jackie' on Netflix and there is practically a Broadway star on every episode. Laura Benanti and Julie White (in recurring roles), Gregory Jbara, Harvey Fierstein, Kevin Cahoon, Celie Keenan-Bolger, Brenda Braxton just to name a few. TONS of familiar faces, and a very interesting/funny show too.
Just in the past few weeks I caught Nikki M. James, John Cariani, and Gabriel Ebert on "The Blacklist". And Harry Lennix, who is a regular on that series, is a well known stage actor out of Chicago.