I have everything he wrote (which includes a number of non-Discworld books, like Johnny and the Bomb, and The Bromeliad Trilogy).

I didn't especially like the Science of Discworld books that much, but he didn't really write them.

One character that showed up in every one of his Discworld books -to a point- was Death.

After Sir Terry got his diagnosis, I noticed that Death stopped showing up in the books.