Mistborn: The Final Empire! If I’m not mistaken, “heist book in fantasy setting” is literally one of the main things that inspired Brandon Sanderson to write this.

Have you read Brent Weeks books? He wrote a trilogy called the Night Angel trilogy, and just released a fourth novel called Nemesis. I admittedly haven’t finished the book yet, but I’m 75% through it and find it so much better than than the original three books. His writing has improved substantially over the years (side note: the Lightbringer series is incredible).

But all this is to say that Nemesis is about a heist. Weeks wanted to write a book about a heist and to try first person perspective, and Nemesis is what came from that.

6 of Crows by Leigh Bardugo - YA heist novel in fantasy (17th century?) Amsterdam.

Patrick Weeks’ Rogues of the Republic series is a pretty good heist series. It is kindle only though.

Mistborn?

I only have poor recommendations after wracking my brain:

The Tower of the Raven by Ann Leckie is the closest I’ve come to a fantasy heist that’s accessible. The heist component is present, but that’s not a tag I’d add to the book without stretching. It does some deeply fascinating things, though.

Then in completely inaccessible fantasy heists we have Skin Game. Book FIFTEEN in the Dresden files. While the series has some other decent heist-like moments, this is a HEIST. And it’s one of the top 5 books of the last few years for me, maybe #1.

But in 3-4 years of my records, that’s about it for heists I’ve read.

Man... I should reread gentleman bastard. Is there a new book out yet?

Edit: Book four appears to be out but I'm wondering if I should reread the series or will I understand enough to be fine just diving in.

Leigh Bardugo - Six of Crows. Multiple heists, fantasy setting and nice YA vibe.

Foundryside by Robert Jackson Bennett. Our protagonist thief accidentally steals a talking key, but I don't want to spoil too much. Plus it's been a while so I don't remember a lot of details. I liked how the magic was like logical programming. How do you make a carriage sitting on an even surface roll forward? Tell it that it's now on an incline.

Edit: Oops. Flipped the author's name