Halo foil ghostfire cards will only appear one percent of the time, making the pull rates incredibly low
In the case of equipping one mana artifact equipment and redeeming mutagen tokens, those would then be free
Midnight Reaper [c]Midnight Reaper[/c] works best when your deck runs lots of creatures, specifically nontoken creatures
Obviously, you dont really want to give up a real creature for the effect all the time, otherwise it is a roundabout way of rummaging, but recurring removal spells is especially potent, and giving up a creature for that is often going to be worth it, especially if you sacrifice a card that brings you some value when it dies
Admittedly, tapping one creature in each of the first two chapters is considerably less good in Commander