Marginalia search has a good explore button for random sites! I have thought about starting a Stumbleupon like tool, but I haven’t got around to it yet.
Stumbleupon was good, partially, because people submitted sites. That requires accounts and moderation though, and getting a community together is difficult.










So it isn’t exactly the same as what I was planning, but there used to be a BannerLink maintained by WSMZ (https://hbaguette.neocities.org/) that isn’t maintained anymore.
I have started maintaining that here: https://j4yc33.neocities.org/stuff/BannerAds
If you have a small website and want to explore more, there are about 17 sites on it right now, and hopefully I will be able to add more.
As time goes on, I might be able to use this database of self-submitted websites to create a sort of small web stumbleupon.