Sol Ring is so ubiquitous to the format that it's shown up in almost every Commander preconstructed deck ever released
Kawaguchi interview (2000): "1" ("For the first year and a half, Tajiri-kun brought in prototypes, but then he stopped working on it.") Hatakeyama & Kubo (2000), p
Then exile it, and you may cast the creature later from exile.) Each creature card you cast from exile enters the battlefield with an additional +1/+1 counter on it
Sure, it costs eight mana, but considering it has delve, which lets you exile cards from your graveyard to pay for its cost, if you could get seven cards in your graveyard, the reward is a sorcery-speed Ancestral Recall legal in formats like Standard and Modern
The problem with it is, the user ends up two cards down and doesn't even get a card from it
But, the upside here is crazy, as getting a 3/3 + whatever your opponents best creature is will be a great deal for 5 mana