We present a scheme for dissipatively generating maximal entanglement in a heralded manner. Our setup requires incoherent interactions with two thermal baths at different temperatures, but no source of work or control. A pair of (d+1)-dimensional quantum systems is first driven to an entangled steady state by the temperature gradient, and maximal entanglement in dimension d can then be heralded via local filters. We discuss experimental prospects considering an implementation in superconducting systems.