The Ten Rings

The refill effect carries this, and the number ten is doing more work than it looks. Raising your maximum hand size to ten first removes the ceiling that would otherwise throw the extra cards away; then the end-step trigger tops you back up to that ceiling every turn. In practice you spend your hand down to whatever you can cast, and it comes back full: not a raw draw-X on a stick, but a governor that holds your hand at a fixed size rather than accelerating it past it. That distinction matters for how the card ages in play. A pure draw engine snowballs toward decking or a discard cliff; this one is self-limiting by design, since it only ever draws the difference. Cast nine cards and refund nine; cast two and refund two. The eight-mana price buys a permanent, hands-off card-advantage tap that asks nothing of you afterward: no mana, no activation, no life. Where most repeatable draw wants to be built around, this wants only to resolve and survive to your end step, at which point it quietly restores your options to maximum and keeps doing so every turn it stays on the battlefield.