core/homeassistant/components/counter/icons.json

{
  "services": {
    "decrement": {
      "service": "mdi:numeric-negative-1"
    },
    "increment": {
      "service": "mdi:numeric-positive-1"
    },
    "reset": {
      "service": "mdi:refresh"
    },
    "set_value": {
      "service": "mdi:counter"
    }
  }
}