As much as I love Cook (have all his sci-fi and fantasy and read it multiple times - much from the 20th century) it feels like the Black Company, Dread Empire, and Instrumentalities series, and Tower of Fear novel all have parts that are not so veiled analogs of the real world (the south, everything, everything, and everything respectively). And the various magic power systems don't seem that well defined; from Tobo and the taken in the former, to the emperors in the middle, to the dwarves in the later, what are there limits or constraints? And there's a bunch of flying whales grabbed from one of his sci-fi stories and stuck in? The mages in some of the Bragi stories seem very close to ones in Fafhrd and Mouser? In spite of that they all seemed fun to me (although the later Instrumentalities didn't seem nearly as good to me as the others).
* Please disregard if you meant the Garrett books, those feel very different from the others.