Have you watched all the episodes?
With "The unofficial S T Index" you have an easily accessible index over all episodes and films made under the Star Trek trademark. All episodes of the Original Series, The Next Generation, Deep Space Nine, Voyager, and Enterprice are listed, as are the movies.
“Star Trek and all related marks, logos and characters are solely owned by CBS Studios Inc. This fan production is not endorsed by, sponsored by, nor affiliated with CBS, Paramount Pictures, or any other Star Trek franchise, and is a non-commercial fan-made app intended for recreational use. No commercial exhibition or distribution is permitted. No alleged independent rights will be asserted against CBS or Paramount Pictures.”