The ADAC is used by most drivers in Germany for car emergencies. However, manufacturer warranties or other car clubs are also an option.
The most well-known is probably offered by the ADAC, but there are numerous – and often cheaper – alternatives that are also available in the event of a car emergency. The cheapest is the KS Club membership for 49 euros in Driver Protection (KS/Auxilia), followed by the “Mobilschutz Basic” tariff from the Bruderhilfe Automobil- und Verkehrssicherheitsclub (BAVC) for 54 euros.