I've heard people proposing a "computational electric heater" in the past where it's just a really powerful computer that can do citizen science processing (or presumably whatever you want on it). I suppose the only issue is cost of sufficiently powerful processors that generate enough heat to actually work as a heater, as well as the thermal regulation system since semiconductors are way more temperature sensitive than a coil of resistive wire, shorter lifespan too I imagine. Though if we can overcome these issues that would be a massive technological milestone.

It would be a really good use of old computers instead of throwing them out though, could use them as space heaters in a place where you don't mind the noise and/or find a way to dampen the noise while allowing the heat to come through.