Another great class mod is the Commissar - Class Mod by ActionJack (no relation to the author of this article, I swear). Though not as obviously overpowered as the Vampiress, the Commissar is still a great addition any team thanks to its highly supportive skill set. The Commissar is capable of buffing allies and shifting their positions, putting you in a prime position to wreak havoc on foes. It's both a fun and awesome class.
Get Commissar - Class Mod via the Steam Community
[Image courtesy of the Steam Community]