There's also BedJet, who makes a fancy-pants bed blower for between your sheets. It's running on an esp32 inside of itself to control the heater and the blower and the remote control, but they didn't quite make it as smart as I'd like.

Fortunately I can just use the ESPHome Bedjet module (https://esphome.io/components/climate/bedjet.html) and just yell out in the middle of the night if I'm too cold.