Finished Pyramids by Pratchet and I really enjoyed the early part where he wrote about the assassin test. Can I get some fanatasy setting book recommendations with the same type of assassin/thief/stealth theme?

Steven Brust’s Vlad Taltos series is all about an assassin. There is about ten of them, and Ace has been reprinting them in collections of three. They are really good, and some of my favorite fantasy. “The Book of Jhereg” collects the first three stories.