There are 3-4 more Mistborn books, too. The next is Alloy of Law if I remember right, and it starts like 100 years later with the world having moved into a sort of wild west era.

Mistborn is also part of Sanderson's greater Cosmere universe. You don't need to read everything in universe to understand any individual series set in it, but there are lots of easter eggs, and they're all governed by the same metaphysics. Other series in the universe include Eltantris (one novel and a novella, I think more planned), Warbreaker (one novel, more planned), Stormlight Archive (5 huge books plus like 3 novellas, lots more planned), White Sands (3 volume graphic novel), and a handful of standalone novels, novellas, and short stories.