He also created illustrations for the Star Wars: Episode III Revenge of the Sith, Star Wars: The Clone Wars, and Indiana Jones and the Kingdom of the Crystal Skull style guides. Howell was also the illustrator of the Star Wars 30th anniversary logo, the Empire Strikes Back 30th anniversary logo, the Star Wars: Clone Wars logo, and the Star Wars Detours logo. Additionally, Howell was featured at the Celebration IV and Celebration V art shows. Howell is also credited with creating packaging illustrations for the Star Wars "electronic helmets" series released by Hasbro Inc. in 2012 and in 2013.
- The Clone Wars: No Prisoners
- Clone Wars Gambit: Stealth
- Clone Wars Gambit: Siege
- The Making of Star Wars Revenge of the Sith