Here are links to some places on the internet that I think are cool. As there aren't a great many, I'll leave them unsorted for now.

Conceptis Puzzles
Tons of classic puzzles online! While most of them are paywalled, there's a rotating selection of free puzzles that change every friday. Requires an account.

A logic-based auto-generated puzzle about a murder mystery. Changes everyday, and increases in difficulty throughout the week. I ship the rival detectives.

Settei Dreams
A wide collection of model sheets used in anime productions. There's some great art out there!

A blog dedicated to anime production. There's some great in-depths analysis of various shows, certain animators' work, or even trends withing the industry.

Anonymous Animal
A sort of internet poem by Everest Pipkin about connecting with strangers, and the degradation that occurs when old web services go down. Active every hour, on the hour, for fifteen minutes. For a better experience, ask a loved one to meet you there!
See also Everest's twitter thread about their process and intent.

The Uncle who works for Nintendo
You're 11 years old and your friend's uncle works for Nintendo. An in-browser narrative horror game. Content warnings are available.

Gameboy Camera Gallery 2022
Did you know that Nintendo made a fully-functional camera for the Gameboy? And that it still has a dedicated community even today? This playable gallery exhibits some pictures taken with the Gameboy Camera. You can play it in your browser, but this game is also a fully-functional Gameboy ROM that you could run on your device! Physical cartidges are even available for purchase (the browser game is free).

Friends at the Table Info Carrd
I'll probably move this link once I have a dedicated category for f@tt on my website. Fantastic fan-made resource that makes pretty much every info about the show easy to access.