core/homeassistant/components/tado/icons.json

{
  "services": {
    "set_climate_timer": {
      "service": "mdi:timer"
    },
    "set_water_heater_timer": {
      "service": "mdi:timer"
    },
    "set_climate_temperature_offset": {
      "service": "mdi:thermometer"
    },
    "add_meter_reading": {
      "service": "mdi:counter"
    }
  }
}