Here are 10 games that can help you in finding a game that is somewhat similar to Star Trek Online. Of course, nothing can fully replace the game itself. If you just need that quick fix to help you in playing a similar MMORPG, you can hopefully find one on this list. If you do not think they are not similar to Star Trek Online to you at all, then you have at least found new games to include in your hard disk drive to enjoy.
You may or may not agree with the list if you have played them yourself, so you are free to suggest better ones. In fact, I highly encourage that you suggest better ones if you do know any.