Robin Hobb's Realm of the Elderlings series. It's right up there with Sanderson IMO.
Reading order is the Farseer trilogy, Liveship Traders trilogy, Tawny Man trilogy, the Rain Wild Chronicles and finally the Fitz and the Fool trilogy. IMO they're all absolute page turners from start to finish. I've read the whole lot twice, some of them more.
It's not quite as daunting as it looks as the Liveship Traders trilogy and the Rain Wild Chronicles follow a different cast of characters from the other 3 trilogies albeit set in the same world and with some crossover.
The one thing that sets it above Sanderson's work for me is that it's complete with no loose threads. Hopefully he gets there one day too!