Elixir of Immortality

The anti-mill insurance policy, distilled to its purest form. Where most lifegain artifacts buy time, this one resets the clock: shuffling your graveyard back into your library is the actual function, and the five life is the consolation prize for spending mana on a deck that was never trying to win the racing game. That single line of text gives it an outsized role wherever a game can grind long enough that running out of cards becomes a real loss condition, and wherever a graveyard-hate opponent wants to exile a library's worth of fuel. Because the artifact shuffles itself back in alongside the cards, it never leaves the deck for good: draw it, crack it, redraw it eventually, repeat. That self-recursion is the whole engine, and it makes the Elixir a repeatable safety valve instead of a single panic button. The five life matters more than it reads, too, since each activation stacks on the last; in a long enough game it becomes a slow but uncapped life faucet. It asks almost nothing of a deck to include (one mana to cast, two to activate) and rewards the kind of attrition-heavy strategy that intends to win by simply refusing to lose.