Common Cause

A generous +2/+2 anthem with a tripwire attached: the bonus only fires while every nonartifact creature on the battlefield shares a color, and the wording is symmetric and board-wide rather than yours-only. In a mono-color deck the clause functions as a clean unconditional team buff, but the moment any opponent fields a creature whose color breaks the unanimity, the enchantment switches off for everyone. This is an anthem balanced not by its rate (which is large for the cost) but by the fragility of the condition it leans on: a single off-color blocker, a token of the wrong color, even your own splashed creature collapses the bonus. The artifact exemption is doing quiet structural work too, since colorless creatures would otherwise fail the share-a-color check no matter what; carving them out lets a mono-white board keep the buff alive while a stray Ornithopter sits in play. The result is a card built around board policing as much as board building: you want a single-color battlefield, and you want everyone else's relevant attackers and blockers either gone or matching. The design comes from a school of white enchantment that asked the deckbuilder to commit to color purity up front, then handed over a bonus no equivalent unconditional anthem of its size would offer, with the upkeep of that condition standing in as the ongoing price.