Go to Venus patrol, head left, go all the way until you get to the big vex complex where you have to activate the conflux for one mission. Yellow bar minotaurs and goblins spawn near the conflux and above on the platform to the left. Or head to Mars and go through the city until you get to the bus station looking area near where the minotaur public event spawns, in the room at the end of that structure a yellow bar minotaur and harpy spawn every few seconds.