With a core of Fable of the Mirror-Breaker, Bloodtithe Harvester, Corpse Appraiser plus a suite of removal, permission and discard, its going to take a lot to break into this archetype
Simply put, any card currently in this zone (a.k.a
5: You may put a creature card with mana value less than or equal to the number of lands you control onto the battlefield from your hand or graveyard with two +1/+1 counters on it

lowered mana cost Many-Winged Angel ability now correctly states "other creatures" Uncontrollable Acceleration is now an instant, it's no longer a strictly worst Blaze Become Death simplified Self-Insert now makes an Avatar instead of an Human token (accompanying token modified accordingly Avatar (SCP-826 ver)) Demonic Contract lowered mana cost Audapaupadopolis, the First City now has an extra cost when entering tapped Black Shuck now self exile when cursing a creature, reduced curse timer by a turn Haunter in the Dark reworded Accelerated Reproduction reworded Contagious Crystal reworded to fix memory issue Malidramagiuan, Emerson's Doom reworded, and is 0/1 so it doesn't die as it enters the battlefield Removed: Vampire Hunting Society for being uninteresting and irrelevant Changed artwork: A Cat Gabby, Gourmet Food Critic (the previous artwork was already a MtG card, oops) Ephemeral Cook (removed text) Hateful Taint Other small changes: Fixed artist name: Cured From The Pestilence Sub-Reality Passage Garfield, the Lonely Self-Replacing Cake James M

I was reading recently about double-faced cards
That's really good, and 6 mana in Commander is mid to late game