You're right on the Bf109E's and G's. AFAIK, although there were testflights with the MC202 and there were some contacts between Swiss and Italian authorities about purchasing some of these birds, it didn't happen in the end.
The Swiss ariforce also flew some MS406 and Bf109D's. Most of the 109E's were licence-built in Switzerland.
But there were also some other planes that were tested by Swiss pilots. Many allied pilots whose planes were damaged over Germany or Italy tried to make it across the Swiss border for an emergency landing or bailout. Many of the planes were then repaired and used for testflights.
After the armistice in 1943 a few Italian pilots escaped to Switzerland with their airplanes.