UPDATE:
I found two nanoTECH ExpressCard/34 cards that are guaranteed by the eBay seller to work with Mojave:
USB 3.0: https://www.ebay.com/itm/2-Port-USB...pple-MacBookPro-15-17-OSX-10-8-2/262393441049
eSATA: https://www.ebay.com/itm/Single-Por...r-Apple-MacBook-Pro-3Gbps-Mojave/252167752639
I haven't ordered either of these... but at least there are two a Mojave compatible ExpressCard/34 adapters available which should be faster than my 17" Early 2008 MacBook Pro's FireWire 800 and USB 2.0 ports.
I found two nanoTECH ExpressCard/34 cards that are guaranteed by the eBay seller to work with Mojave:
USB 3.0: https://www.ebay.com/itm/2-Port-USB...pple-MacBookPro-15-17-OSX-10-8-2/262393441049
eSATA: https://www.ebay.com/itm/Single-Por...r-Apple-MacBook-Pro-3Gbps-Mojave/252167752639
I haven't ordered either of these... but at least there are two a Mojave compatible ExpressCard/34 adapters available which should be faster than my 17" Early 2008 MacBook Pro's FireWire 800 and USB 2.0 ports.