I have an old telephone line serial modem made by Practical Peripherals that also had faxing ability. Occasionally I do still find myself wanting to send a fax, but it had gotten to the point where only one old computer still had a serial port, and using it even on that seemed like a dicey affair. (I'm not sure if the hardware was going South, or if support for serial ports in the software wasn't as good or what.) Anyway, I finally broke down and for a few bucks bought a usb fax modem, and it works well and smoothly. The only thing I miss is the song of the phone modem as it makes its connection since the new gadget doesn't have a speaker.
The other thing replaced is the parallel port for printers. I still have an old fashioned printer cable and a printer that has both parallel and usb connections on it. So, one time, just for grins, I tried to use it to connect that same old computer that had a parallel port, and I couldn't get the system to recognize the printer, whereas when connecting by usb it's detected automatically. (I vaguely remember in the old days, one had to go through various incantations to get linux to recognize a printer, I must still have my notes around somewhere, but too much work to try to dig them out.)