NOT a game about catfishing people. I have yet to find anything of that nature. Catfishing is a game about guessing Wikipedia articles by their categories, which is probably more fun anyways.
Rescue or steal dragon eggs, then 'raise' them by having people click on that dragon's page. Once a dragon is fully grown, you can try to breed it with other dragons, and start the whole process over again! You can help a dragon grow by adding it to a site or forum signature; there are also dedicated 'hatchery' sites to get views, such as Garden of Eden.
Large retro game preservation project (note that even the 3DS is retro now! :'[ ). It's not just games-- this site has manuals, reviews romhacks, and more!
All sorts of guides and tools for the mainline Gen IV games. Check out the shiny hunt generator, it gives you a Shiny Pokemon to hunt AND advice on how to hunt it!
Animal Crossing: New Horizons fansite with miscellaneous tools and guides. The main draw is the ability to share custom designs, island tunes, and dreams, but the K.K. Slider album checklist is also quite nice.