If you get the chance, check out the list of her work on IMDB.com. Comedies, dramas, movies, television, cartoon voices... I don't think there is anything Pat Carroll didn't do.
Most of my exposure to this talent came on game shows. She was really good at "You Don't Say" and several others, including "Match Game." Pat Carroll knew how to have fun, and still take the games seriously. You would be amazed at how many celebrities don't get it right. She was dependable and I suspect that's what led to so many bookings.
Pat Carroll might not be the most prominent name on the list of people we've lost recently. She is among the most important.