In addition to the character sketches and the ship design for the U.S.S. Excalibur campaign, I occasionally did some other art for specific "episodes" of the campaign. Here are two pictures from a "Mirror Universe" adventure and two from a couple of adventures where the crew visited alternate futures, one more straightforward future (future Starfleet uniform pictured) and another where the Federation, Klingons, Romulans, and Cardassians had united into a single Alliance (Alliance starship pictured).

Mirror Spock
Mirror Data
Future Uniform
Alliance Starship