Seconding a lot of other stuff, go me. You can read them chronologically but yeah, you're not necessarily hitting the best introductory material that way. Discworld novels are pretty easily broken up into sub-groups: City Watch stuff, Rincewind the failure wizard, the witches out in the goffic mountain country, Death books, and Moist (which hits on some of the Watch's city-centric stuff in a different way), along with a handful of more or less standalone protagonists.
I'd definitely agree with hitting the Watch first since Sam Vimes is seriously just my favorite goddamn fictional person and the city of Ankh-Morpork is an excellently realized metropolis where most of the best stories happen. Guards! Guards! is a good introduction, then Men At Arms/Feet of Clay/Jingo are all absolutely top shelf Discworld installments.
Death is second preference for me as far as Discworld goes. Mort is the first book in the series that really solidifies the focus transition from genre parody to satirical humanism, Death being, somehow, among the most humane entities in the world and whose off-kilter perspective is always fun to read. I like Mort, Hogfather and Soul Music a great deal, although my extreme bias toward the subject matter of the latter may have some influence here ("They can't stop us. We're on a mission from Glod.") I barely remember Reaper Man despite having read it a couple times, though.
Witches and Moist books are okay? Still entertaining because it's Pratchett, but I find them squarely a tier below the above. Apparently a lot of people are super keen on Moist, but he didn't hit me quite the same way (I haven't read Steam or whatnot yet, though).
Rincewind easily least priority, I'd advise. These are mostly early installments when Pratchett was just finding his feet, and the humor tends to be a lot broader than it is in his best work (but even at his worst, Terry Pratchett was still funny; it's just that, at his best, he was funny while also being the nicest teacher you never had). Interesting Times is probably the best out of these? I may be biased because it's the first Discworld book I read.
As far as standalone Discworld books go, I would actually strongly recommend Small Gods.
Non-Discworld books, Good Omens is absolutely a thing. Nomes are pretty neat too, a very smart guy writing for a young audience without talking down to them. There's some other stuff that I haven't read, dude was super prolific. In light of events, I'm probably due for another full series reread, it's been like five years man.
