core/homeassistant/components/snips/icons.json

{
  "services": {
    "feedback_off": {
      "service": "mdi:message-alert"
    },
    "feedback_on": {
      "service": "mdi:message-alert"
    },
    "say": {
      "service": "mdi:chat"
    },
    "say_action": {
      "service": "mdi:account-voice"
    }
  }
}