Here is a list of several links that are useful if you're getting yourself into retro hardware!

RetroRGB - covers the best ways to get the highest quality video out of your retro consoles. Whether you just want to get it up and running on your flatpanel, or you want to go all out with a CRT, this site covers essentially every console imaginable.
KHInsider - website full of video game music for download
CRT TV Simulator - a CRT in your web browser
RemoteCPU.com - a giant list of programs for Windows 98.
Windows 98SE Utilities - a good list if you're just looking for the essentials.
Ancient Win95 Software List from Andrews Uni - most of the links don't work. I'd use this as a list for finding the names for certain programs, then search more from there.
Walkx.org/midi - a ton of midi files!
The Floppy Disk Museum - a museum for floppy disks, which is small enough to fit on a floppy disk
Fun Kirby Utilities - a bunch of programs centered around Kirby!
noclip.website - fly around various video game worlds
Super Famicom Games - Official Nintendo site from the 90's which showcase games for the Super Famicom

This list will be updated as I find more stuff!