I really like the newly added feature to retrieve the device from an entity_id (device_id(entity_id)), and use that to get all sibbling entities (device_entities(device_id)).
It would be great if this could be expanded to get the parent integration from a device (eg. integration(device_ID)).
An example where I would use this is the Plugwise Beta integration.
Since all plugs are named by their mac address it is not possible to predict which devices are available.
When we have one entity or device, we could navigate up the tree to the Plugwise_stick integration and get a list of all devices.
Edit: I discovered that {{ device_attr('device_id', 'config_entries') }} returns the parent integration, but I haven’t found a way to go down the tree and retrieve all devices from this integration.