Hacker News is great because there a lots of interesting discussions and articles especually on Ask HN. It feels like a high quality tech/programming subreddit but without the disadvantages of reddit.
https://news.ycombinator.com/
I used to be a mod on Nonsensopedia.
https://nonsa.pl/wiki/Strona_głó
It was a wikipedia-like thing, but with humorous stuff. I think it is abandonned now. There were a lot of garbage, but also some really well-written satires, that took a lot of writing skill of many authors to make. It is in polish, so most of you probabbly won't be able to read it. Reading it through a translator is not a good idea, because it contains A LOT of language humor and references to polish culture/memes/politics
Neocities! It's a spiritual successor to Geocities from ye olde internet, and it rocks. Poke through the directory of sites, there's some wild stuff on there.
The SCP wiki is always a fun place to lose a couple of hours. Here’s how they describe themselves:
The SCP Wiki is a collaborative speculative fiction website about the SCP Foundation, a secretive organization that contains anomalous or supernatural items and entities away from the eyes of the public.