I don't know who owns the IP for the old D&D cartoon characters, but they're using WotC's dragon designs for Tiamat's heads. I wonder if there's any copyright violation going on in this ad?
Guards Guards and Mort are the best starting places, in my opinion. Small Gods and Wyrd Sisters are good too.Thank you both. I've only read the first two and following to the reading order, I shouldn't even read those two according to the author himself.
https://upload.wikimedia.org/wikipedia/commons/1/12/Discworld_Reading_Order_Guide_3.0_(cropped).jpg
If it wasn't that expensive in French, I would buy them all.