Nathan, may I ask you to elaborate?
Is it about "gather all device_trackers & show them on a map"?
Some remarks:
Some integrations (like BLE) create tons of device_trackers; these entities may be not needed on a map.
A custom auto-entities card of Thomas Loven works fine with the ha-map-card; it creates a list of needed entities (could be persons, device_trackers, zones, sensors with coords - according to defined criteria) and then passes these entities (or dicts - including required per-entity options) into ha-map-card.
Nathan, may I ask you to elaborate? Is it about "gather all device_trackers & show them on a map"? Some remarks:
ha-map-card
; it creates a list of needed entities (could be persons, device_trackers, zones, sensors with coords - according to defined criteria) and then passes these entities (or dicts - including required per-entity options) intoha-map-card
.