- Aldi (supermarket chain), founded by the Albrecht brothers, thus ALbrecht DIskont
- Adidas, founded by ADolf DASsler
- Mercedes-Benz, named by Emil Jellinek-Mercedes after his daughter Mercedes, initially with Daimler which then merged with Benz
- Audi, founded by August Horch. Initially founded as _A. Horch & Cie. Motorwagenwerke Zwickau_, he later lost the rights to the name "Horch". He named his new company "Audi", which is a translation of his name into Latin: in German, "horch" is the imperative for "horchen" (to listen), which maps to "audi" as the imperative for "audire" in Latin
And then there are a just a ton of companies named after their founders (Porsche, Bosch, Siemens, …) but I'm not sure if these count :)