In May, 2021 we had the chance to spend two days at the PS Speicher collection in Einbeck, Germany.
During Summer, 2021 if you are in the Frankfurt area in Germany you are well advised to visit the Central Garage museum in Bad Homburg.
The Matra Museum is located in Romorantin, France. You'll see there all the cars, that made MATRA (Mecanique-Aviation-Traction) history and particularly most of the race cars and engines.
We visited Winfried A. Seidel's excellent museum, which is situated in Ladenburg, near Mannheim in August, 2010.