Twinflame Travelers

Doubling triggered abilities is a mechanic with a long pedigree, from Panharmonicon on the artifact-and-enchantment axis to Yarok on the permanent-ETB axis. This one narrows the lens to a single creature type and, crucially, does not limit the doubling to enters-the-battlefield triggers. Any triggered ability from another Elemental you control fires twice: attack triggers, upkeep triggers, death triggers, anything that goes on the stack. That breadth is what separates it from the ETB doublers. A Panharmonicon effect reads narrow and plays wide, but it still needs a body of permanents that trigger on entry to matter; this asks instead for a critical mass of Elementals whose triggers span the whole turn, then rewards you for stacking them at every step. The flying body keeps the enabler relevant on an empty board rather than parking it as a do-nothing enchantment that dies to a stiff breeze. The Elemental subtype is the constraint that pays for the effect: a tribe deep enough to build around but shallow enough that the doubling does not touch your whole battlefield indiscriminately. The color pairing tells you the intended mode. Blue-red Elementals lean toward tempo and burst rather than the grindy value engines a green-based doubler would assemble, so the reward tends to arrive in a single explosive turn rather than accruing over many.