Eidolon of Philosophy

In Commander, Eidolon of Philosophy is a fringe inclusion — the five-mana activation competes with everything else you want to do on turns four and five, and most blue or black decks have better draw options at that cost. In Pauper, where card advantage at common is genuinely scarce, it's more interesting as a late-game mana sink, though the format's tempo demands still make it a tough sell. Across Legacy, Modern, and Pioneer, the card is simply too slow and too low-impact to see meaningful play. Oathbreaker follows the Commander read: fine if you need the effect at common rarity or in a sacrifice-matters shell, not competitive otherwise.