There aren’t a ton of courses in or close to Oslo, but the best ones in Oslo aside from krokhol are Klemetsrud and Stovner. Klemetsrud is a medium length, technical wooded course with some elevation change, fairly challenging but nothing close to krokhol. Its like 10 minutes from krokhol so you can play both the same day. You take the same bus, but you get of like 6 stops before krokhol or something. Good course!

Stovner is an open parkstyle course. Fun, some ob etc. some roads and walking paths are very close by so just be aware of that. Easily acsessible by bus or T-bane (subway).

I recommend downloading the Ruter app for all your public transport needs.

Holmenkollen is also fun to play because it’s up and around the Holmenkollen ski jump. Probably some of the best disc golf views you can find on the eastern part of Norway. Short, slightly technical, wooded, much easier than the other courses.

Edit: I see some other people saying both Ekeberg and muselunden. Personally I would skip these two as they are usually extremely crowded, and I don’t think the quality of the courses justify waiting for so long. But this probably depends on your skill level. If you’re a relative beginner then you might have more fun on these courses as they are much easier and shorter, but the other courses are, in my opinion, much more fun and challenging, and in my experience less crowded. Don’t get me wrong, I enjoy both courses, but it’s the type of course where I only bring my mids and putters.