The British Oliver Manufacturing Company had various european portable typewriters branded as Oliver. A great article by Will Davis called Olivers in Transition outlines the history of these machines in further detail.
The first portable that was sold as an Oliver was manufactured by Fortuna Buromaschinen GmbH of Berlin, Germany. This company was formed from Stolzenberg-Fortuna, which used to distrubute Olivers as the Monopol-Stolzenberg and Stolzenberg. This portable body style was also sold under the names Europa and Junior.
Between serial numbers 80000 and 90000, S.I.M., an Italian typewriter company, started manufacturing portables under the Oliver name. These machines were also branded as Augusta, Nuova-Levi, and Continental. All of these various bodystyles were intermixed, follow the same serial number scheme, and manufactured until the end of World War II.
After World War II, the British Oliver Manufacturing Company rebranded a Swiss machine called the Patria.
Another Oliver portable was branded as "Oliver Courier", "Conquerer", or simply "Oliver". This body style was also sold as a Patria, Japy, and Voss Privat.
The M-series Voss portables have been found under the Oliver name. I have seen the Voss MDT10, MT10, and MT13 (which is a wide carriage MT10) rebranded as Oliver. These were also branded as the Oliver Consort. Voss later used the same body styles but with model numbers beginning with S, so any of these models may have been sold under the name Oliver. The serial numbers are intermixed with the standard Voss serial numbers. Voss machines were produced until 1965, but the Oliver Voss machines were most likely discontinued when the British Oliver Manufacturing Company shut down in 1959. See Voss Portables by Will Davis for more information on general Voss models.