In my opinion, the BEST of his other writing is the Stormlight Archive - The Way of Kings, Words of Radiance, Edgedancer (short story) and Oathbringer. Such wonderful long books full of awesome. The downside to it is it's not completed, and it'll be a while. It's set to be a 10 book series with two 5-book arcs.
Elantris and Warbreaker are two other books set in the same universe. It's not a bad idea to read Warbreaker before Stormlight, for inter-book references. But IMO these stories are not as gripping to read.
Others have mentioned the second Mistborn series. It is also really good. It isn't complete, but the final book is due next year...so if you're still in a Mistborn kinda mood, go with that!
There's also Arcanum Unbounded - a collection of short stories set in the Cosmere. Some are stand-alone, some are attached to novels. There are a couple of stories you shouldn't read until you've read the relevant novel.