Universal Automaton

Changeling on a bare artifact body is the most stripped-down expression of the mechanic: no evasion, no keyword rider, no drawback, just a one-mana 1/1 that answers to every tribe at once. That total emptiness is the point. Tribal payoffs check a creature's types, not its flavor, so this reads as an Elf to Elvish Archdruid, a Goblin to Goblin Chieftain, a Sliver to any slivers-matter effect, and a valid target for anything that fetches, buffs, or counts a type by name. Being an artifact on top of that widens the net further, opening it up to affinity-style counts and metalcraft alongside the tribal grid. What makes it worth keeping around rather than a novelty is that it solves a structural problem for narrow tribal decks: the shells that want a specific creature type often cannot fill twelve or sixteen slots at a playable rate, so a colorless, type-agnostic body that plugs any of those holes is more valuable than its stat line suggests. It asks nothing of your manabase and belongs to whatever tribe your deck happens to be. The tradeoff is exactly what you would expect from a card that is everything to everyone: a 1/1 that does nothing on the battlefield until a payoff cares about what it is. It is a connective piece, not a threat, and it was built to be one.