Some of the Fallen Hunted cards unlock when completing the House of Wolves chain fully. I think some may be bugged still. If your friend has other characters to start up/complete these chains on, it would not hurt to try completing these chains on the main character. In case there are a couple of Fallen Hunted cards left over, there are a couple of spots on Patrols where you run into the lower valued bounty enemies, notably on the moon with the Archer's Line hive zone. Funnily, the door behind that group that leads to the Shrine of Oryx is no longer closed on Patrols. I think there might be some of the Tracer Shanks that still spawn in Patrol Cosmodrome when you go back about halfway towards the game's very beginning from the Divide. I cannot recall how spawns of Fallen Hunted enemies in the satellite zones on Venus (Cinders, N-Gen, the Simiks-3 area, and Endless Steps) still are active, if any.

I think by playing the HoW quest line since my friend who just started and completed the story has them