The following types of large guard dogs can be raised in cities:

1. German Shepherd: German Shepherd is smart, loyal and easy to train, and is often used as a police dog and military dog. Due to its excellent guarding ability and stable character, it is also loved by many families.

2. Doberman Pinscher: Doberman Pinscher is elegant in shape and has extremely high alertness and loyalty. They are generally easy to train and very family friendly, so they are also a common guard dog breed in cities.

3. Rottweiler: Rottweiler is strong, loyal and brave. They are very loyal to their families and also have good protective abilities. However, it should be noted that Rottweilers require early socialization and correct training to ensure a stable personality.