Primitive Etchings

Card advantage that scales with how creature-dense your deck already is: the engine pays out only on the first draw of each turn, and only when that draw is a creature. That single-draw clause is the whole balancing act. It cannot chain off itself within a turn, so the per-turn ceiling is one extra card, but the floor is set by your own deck construction. Fill a green stompy shell with nothing but fatties and the trigger becomes nearly free repeatable advantage; run a spell-heavy build and it sits there doing nothing. The reveal is mandatory, which is the small cost paid for it: opponents read your draws and learn whether you whiffed. The design holds together because it rewards the kind of deck green already wanted to build, a curve of creatures, instead of asking you to bend toward an artificial trigger. It is a draw engine that asks not "what do you cast" but "what fraction of your library is a creature," and it answers that question once per turn, every turn, for as long as it survives. There is no sequencing trick to exploit, either: the trigger watches the first draw of the turn no matter when it happens, so the only lever you can pull is the ratio of creatures to spells you registered before the game started.