Any ESP8266-based or Zigbee smartplug will do. If you get an ESP8266-based one, get one that comes with Tasmota preinstalled, then you don’t need to open it up and flash it. Don’t get an ESP32-based one.
If you run Tasmota or use a Zigbee plug, you need to do the detection in Home Assistant or Node-RED or whatever you’re using. Personally I do it directly in ESPHome:
binary_sensor:
- platform: analog_threshold
id: machine_running
name: "Washer running"
icon: mdi:washing-machine
sensor_id: power
threshold: 5
filters:
- delayed_on_off: 60s
You know, the rest of us are using a smart plug with energy metering to find out if the dryer is finished.
Are there though?