Most of you won’t need access to an old, obsolete browser. Sometimes people still want them supported on their web sites. Doing that is a pain, and hardly worth the effort since so few people still use them. For quite a while, I didn’t know where to find any of the older stuff.
Evolt.org has a browser page with more browsers than I’ve ever heard of. I must admit, I’m scared to install them because of incompatibilities, but if you need them they’re still available.