If we were to rely on the answer for this question involving quadrantsthis question involving quadrants then there have been several episodes and movies taking place in the Beta quadrant.
Star Trek the Undiscovered Country takes place in the Klingon Empire, which is in the Beta Quadrant
Star Trek: Nemesis takes place in the space around Romulus and Remus (as well as the neutral zone), which is also in the Beta quadrant.
There are several episodes of most series (I can't think of any in Voyager off the top of my head) which involve either the Romulan home world, the Klingon home world, or different planets in their respective empires.
