A-Briar Hydra

Domain is the mechanic that reads your basic land types and converts a stretched, multicolor manabase into a scaling number, and here it drives a counter engine rather than the flat bonus most domain cards settle for. The 5/5 trample body is deliberately plain, because the reward lives in the trigger, not the stat line. Trample is what makes the trigger fire reliably: chip damage through a blocker still counts as combat damage to the player, so the attack lands even into a crowded board. Connect, and a chosen creature you control gets +1/+1 counters equal to the number of basic land types among your lands (a two-color build gets a modest bump, a three-color wedge lands three, a five-color shell the full five). The routing is the design choice worth reading. The counters land on any creature you control, so the card flexes between two modes: point them at the Hydra and it becomes a self-improving threat that connects harder each turn, driving more counters through its own trample; point them elsewhere and it plays as a repeatable growth spell for last turn's monster, though whatever you feed keeps only its own evasion, not the Hydra's. It rewards the manabase you were already assembling rather than any specific partner. As domain payoffs go it sits at the aggressive end of the mechanic's history: most scale a one-shot spell or a static number, while this one compounds for as long as the attack keeps landing.