Yes, 'Eric' is a good Discworld novel. It has Pratchett's signature humor. The characters, like Eric the demon and Rincewind, are engaging and their misadventures are quite entertaining.
The last Discworld novel is 'The Shepherd's Crown'. It was published posthumously as Sir Terry Pratchett passed away in 2015. This novel continues the rich tapestry of the Discworld series, with all its unique characters, satirical humor, and imaginative world - building.
I would recommend 'Guards! Guards!'. It's a great starting point as it introduces the city of Ankh - Morpork and the Night Watch in a really engaging way. There's a lot of humor, a good mystery with the dragon plot, and it gives you a feel for Pratchett's unique writing style.
'Equal Rites' can be a good starting point as well. It deals with the idea of female magic in the Discworld, which is a unique concept. The story follows Eskarina Smith, a young girl with magical potential. It has Pratchett's trademark humor and a story that will draw you in. It also gives you an introduction to the magic system in the Discworld, which is quite fascinating.
I would recommend 'Guards! Guards!'. It has a great story with the Night Watch in Ankh - Morpork. The characters are really engaging, especially Sam Vimes. It's a good introduction to the world - building of Discworld, with its unique city full of all kinds of strange creatures and characters.
You might enjoy 'Witches Abroad' as it has a mix of magic, adventure, and witty characters like in Good Omens. The storylines have a comparable charm and wit.