It takes long amounts of time to find great websites, so sit back and relax as I have dug up some diamonds in the ruff. The further we go the more obscure they'll get.
This is a well known website. Mostly for its way back machine which many consider its best feature but it has other stuff. It's one of the biggest archives of games, books, and other media. I've used it previously to get old games to restore and to dig up old info on a small town.
When chat gpt can't do it, this is where I go. It is a good source of the basics for almost every popular programming language.
Neal.fun has gotten very popular in some corners of the internet for his games, but many people don't know about the many other games and factoids on the website. He is also always adding new games.
Nation states is by far one of if not the best nation sim website. It has a massive online community that allows for nation rp, global policy, and joining fun small communities. The website is certainly a bit of a longer term investment tho.
It is extremely hard to find a good height map online, and this interactive world height map certainly helps. This website allows you to see the height data of any where in a small slice with pretty coloring.