The difference between these cards and Game Changers is that Game Changers, while strong, are labeled Game Changers with Commander's social setting in mind
Ferrous is even more powerful in the 99 of Multicolor Matters commanders that have access to more colors like Rienne, Angel of Rebirth, Niv-Mizzet Reborn, and my personal favorite, Ramos, Dragon Engine, which I love building as Lucky Charms
Anything that costs 6 or more automatically cascades, letting you chain spells for massive value
Thats already a $20-$30 discount on the Limit Break precon alone
The spells mentioned above won't be very good without a way to load your graveyard with threats
I know you want to find out how I ever could do that