Harvester Troll

Value paid up front, with a fuel clause narrow in what it accepts but wide in when it applies. The 2/3 body can arrive as a 4/5 the moment it lands, because the enter trigger asks you to sacrifice a creature or a land in exchange for two +1/+1 counters. The design cleverness is that lands count: in a game where you have drawn more of them than you will ever need, the troll always has something to feed itself, so it rarely strands you on the fair body. The optional wording matters too. Nothing forces the trade, so when every permanent is still pulling weight you decline and take the plain 2/3. Note the timing, though: this is a sorcery-speed enter trigger on a creature without flash, so it resolves when the troll comes down and cannot be held back to consume a creature already targeted by removal or dying in combat. The sacrifice is proactive planning, not a reactive outlet, which limits what the card can rescue. What it does well is convert dead weight into stats: a creature that has outlived its purpose, or a spare land past its usefulness, becomes two counters, and in a shell built to spend permanents that sacrifice can also feed death triggers. A green role-player whose ceiling tracks how much surplus you have to convert, and whose floor is a modest body that never quite reads as a wasted card.