Fun with Unity's Navmesh Agents and some steering behaviours. I created three behaviours: circle perimeter, circle random, and wander. Perimeter just has the agents circle around a center point, random has them pick random points to navigate to around a center point. Wander has them choose a new position to navigate to, or return to their starting location if one cannot be found. I also created an orbit camera to creep on them with.
Perimeter behaviour has them run in circles.
Wander behaviour has them wander around an environment.
Configurable orbit camera can also orbit a target.
Behaviours are driven by scriptable objects, which makes it easy to setup different behaviours and swap them in.