Actually, I've had a difficult time finding much information about what's still available for Win98. When one visits the update sites, where the information should be, the site looks at what you have installed before it finishes letting you in, and then it "resists" telling you anything not related to what you're running. As I don't have a Win98 system running any longer, I can't get in as a Win98 user.
There are a few other places where some information is "findable" but most of it is pretty vague. If you have Win98, you can go to the Windows Update page at Microsoft and they should tell you - but they don't seem to want to tell me.
I do have an old laptop with Win95 on it (memory chips discontinued and it can't load even Win98 with what's installed); but if I take it to Microsoft they'll probably just giggle and make fun of me.
If you are still using Win98SE, I'd strongly urge that you try to download the update package and save it with your Win98 Installation disk(s), in case you need to reinstall sometime in the future.
Anyone using WinXP that didn't get SP2 with the original installation should also IMMEDIATELY order the free SP2 update CD from Microsoft and put it with their WinXP installation/recovery disk, if you don't already have it there.