With the Memento design pattern you can save and load the state of an object. This paves the way for functionality such as undo and redo.
The Mediator Design Pattern reduces communication complexity.
The iterator design pattern is a standardized way to iterate over any kind of collection.
The Command design pattern decouples sender from receiver.
The Chain of Responsibility design pattern chains different classes inside each other to create a chain of escalation. An appeal to the chain makes the right handler answer the call.