Now I am not to sure if you could count is an easter egg
Spoiler incase your new and haven't been to Balmorra -
On the Republic version of Balmorra , the mission where your helping the resistence retake Sobrik the 2nd stage to the bonus mission attached to it makes you change the cantina soundtrack to a more 'patriotic' song and when you do change it the song that is played is the theme to Knights of the old Republic