In this video, Paul Hanson breaks down three very easy to use minor pentatonic scales that sound great over a minor (dorian) mode.  Minor pentatonics are built by the using scale degrees 1, b3, 4, 5, b7.  The pentatonic scales that he uses are built from the 1, 2, and 5.  So in the key of G minor those scales are G minor pentatonic, A minor pentatonic, and D minor pentatonic.  As you can hear, the different pentatonic scales sound different when played over the G minor,  but they all work rather well as all the notes sit naturally inside the G dorian mode.