Too many to list. DLR - Germany's NASA - is a key player in Europe's space industry, so it draws all kinds of space companies to its neighbourhood.

EDIT: those two links might give you a quick overview:

- https://spaceindividuals.com/space-companies

- https://spaceindividuals.com/space-jobs?country=Germany (over 50% of all listed, but not surprising, since the site's owner is in Germany as well)

Right now, I'm trying to map the industry myself.