I loved ITSOL! Just reread it last month actually. I remember just being on the edge of my seat for the last third of the book If you enjoyed that I would recommend The Powder mage Trilogy by the same author, he does a good job of mixing a mystery investigation POV and a more action oriented one, just like in ITSOL, and I find it very engaging. Also The First Law Series. I think you'll enjoy the tone and mix of Known and Unknown Magics in those series similar to ITSOL.
I can also recommend The Will of The Many and The Blacktongue Thief, which were two of my books of the year for their releases, if you're looking for fantasy with a different tone than your standard, run of the mill sword and magic series
I've read all of the WOT books twice now (but multiple attempts...) And while they hold a special place in my heart and are instrumental in helping shape the modern epic fantasy scene, I'm kinda iffy of recommending them to people, especially those just getting into the genre. Be interested to hear your (and others!) thoughts on this as you get deeper into the series.