Retro Computing

Protoweb - Proxy for the old net. Some function just as good as they did back then
The Old Net - Website that connects to Archive.org's wayback machine. Also has a proxy.
Frogfind! - A search engine powered by DuckDuckGo that supports old computers.

Interesting Github/lab projects

Web Rendering Proxy - Use your modern computer to allow an obsolete one to use it.

Image Tools

Photopea - A free online photo editor.
Dither it - A free website that allows you to dither photos. Can save a lot of space.

Utilities

Disk Tools

SD Card Formatter - Software created by the SD Association to format an SD card.
h1Testw - Verifies storage drives to make sure their storage is the correct size.

Download page is in german, but it should be fairly obvious how to download it.

HP USB Disk Format Tool - Created by HP, this tool is still recommended by many drive makers.
Balena Etcher - Bootable USB drive creation tool. Select the image, then the drive, then it does all the work!
Rufus - Does the same job as Balena Etcher, but has more options.

Shops

Stickers

Geekenspiel - Retro computing stickers

I've seen his stickers before on Youtube channels such as LGR and they look very high quality.