Unit, running
A hex unit drawn as an open loop around a solid core: a worker mid-task. Units tile, so a fleet is a cluster of them.
Orbit
A core inside a running orbit. Clear motion, but at 16 px it reads as a loading spinner.
Actor
A pointer with a target: acts on its own. Strong for computer use; easy to take for the select tool.
Beacon
A core broadcasting. Reads as live or wireless rather than as a worker.