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Richard Dean Anderson appeared in two Stargate spin-off series: Stargate Atlantis and Stargate Universe. These spin-offs explore different aspects of the Stargate universe, introducing new characters and storylines while maintaining the core themes and elements of the original series. Stargate Atlantis follows a team exploring the lost city of Atlantis, while Stargate Universe focuses on a group of humans traveling on a long-range starship searching for a new home.