Microsoft has never released a service pack for Windows98 SE! So here it is; the 'unofficial Service Pack 2.1a'. It contains all Windows98 SE updates from Windows Update site and more integrated into a self-extracting and self-installing pack like Microsoft's update files.

You cannot choose files individually. However, the pack installs only required fixes for your system.
This servicepack is for Windows98 SE ENGLISH only

Download Windows98 unofficial ServicePack v2.1a