When I need a driver I Google for it. I include the product name and model number
in the search. The drivers are out there if you have the patience to look for them.
I am never satisfied until I compare drivers from a few different sources, you are
likely to find different versions on offer. It is true that a lot of so-called driver
download sites are all about downloading and installing some third party app supposedly
to scan your system. I don't trust them.
If there is a single website offering a comprehensive collection of drivers for old
hardware and old OS's for free I don't know about it.
See if this suits your purposes.
http://www.opendrivers.com/driver/213134/creative-modem-blaster-v.92-di5631-driver-win98-free-download.html
Once I entered the code and was taken to the download page I found the Official Driver
Download links dead. A little lower down the links to the backup servers were good.
Finding these drivers took about two minutes. You could no doubt come up with a few
other places to download drivers for your modem if you spent maybe half an hour.