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.
Well, 'Night Watch' is a very significant Discworld novel. It takes the reader back in time in the city of Ankh - Morpork and shows how the city's Watch, the police force, came to be what it is in the present - day novels. Also, 'Reaper Man' is important as it deals with Death's sabbatical from his duties and the chaos that ensues. These novels are important as they expand on the lore and the complex web of relationships in the Discworld.
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.
I think 'Mort' is also very popular. It has a unique story about Death taking on an apprentice, and the graphic novel version makes it even more accessible and engaging. The art style is really appealing to many fans of the series.
You can start by looking at websites like Archive of Our Own (AO3). It has a large collection of Discworld fan fiction sorted by different categories like characters, story arcs, etc. FanFiction.net is also a good place. There you can find a wide range of fan - created stories about Discworld.
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.
Definitely 'Wyrd Sisters'. It's a brilliant take on Shakespearean themes within the Discworld universe. The three witches are such memorable characters. The way Pratchett weaves the story, with all its political intrigue and magic, makes it one of the top Discworld novels. There are also many other great ones, but these are some of the most highly regarded.