Samsung Galaxy Fold can be compared with devices like Sony Tablet P or Toshiba Libretto W100, because they fold into a tablet with two screens in the same plane.
But it is also quite appropriate to compare with communicators, whose external interface was used for phone calls, and the device itself was laid out to increase productivity. From this point of view, the Galaxy Fold is the result of more than 20 years of evolution of communicators.
The photos below reflect 24 years of the evolution of communicators, starting with Hewlett-Packard OmniGo700LX Communicator Plus (released in 1996) and ending with Samsung Galaxy Z Fold 2 (released in 2020).