Dauntless Dourbark

The body counts two populations at once: every Forest you control and every Treefolk you control, and because the Dourbark is itself a Treefolk, a four-mana cast off four Forests already lands as a 5/5 (four Forests plus itself), with every additional Treefolk pushing the count up by one regardless of what those creatures otherwise do. That double-counting is the whole arithmetic, but the trample clause reveals the brake built in beside it: trample only switches on while you control another Treefolk, so the card refuses to be a standalone threat and insists on the supporting cast it was built to reward. A Forest-only build leaves a fat but groundbound creature that a lone chump blocker can stonewall. Lean into the tribe and the picture inverts: each additional Treefolk simultaneously grows the body and turns on the trample that lets all that bulk spill through a blocker, so the same card that wanted a deep mana base also wants a wide one. Its stats come largely from the rest of your permanents, but unlike a pure lord that only buffs others, it brings its own bulk to the field. It is the count-the-board creature and the payoff that count was meant to feed, resolved into a single casting.