WTH there are no "abstract" entities and/or cards?

I called them abstract but better term would be templates. This term is already used for entities that are based on templates but I mean templates for entities. It could be something like lightweight integrations.

How I would see it:

      platform: mqtt
      unique_id: "mylight_{{some_id}}"
      object_id: "mylight_{{some_id}}"
      name: "{{name}}"
      state_topic: "my/topic/{{some_id}}"
      command_topic: "my/topic/{{some_id}}/cmd"
      payload_on: "1"
      payload_off: "0"

    - some_id: "101"
      name: "Kitchen Light"
    - some_id: "102"
      name: "Bedroom Light"

Something like this would be great both for entities and also for cards as well. It would greatly simplify large smart homes. Currently there is a lot of repetition required or need for a custom integration.

That’s what I would expect to see under the name “template”. For current templates I think the word “derived” would be more suited.