How can I transfer my old 3.5"-based font packages to a CD for installation on my current PC? (Windows 7)
USB floppy drives are still sold. But I'm not sure I'd bother... if they are Adobe fonts they are likely to be Type 1 fonts, and these are being phased out - in a year, no Adobe apps will read them.
You will need a floppy drive, but I would transfer directly to your PC hard disk. But as @Test Screen Name said, Type 1 font support will be phased out soon. Older applications, however, will still be able to access and use Type 1. On a different note, you really should change to Windows 10.