It’s not like a written or verbal list though. I also have no internal voice so that wouldn’t make sense. It’s just like the concept of what I’m thinking of is right there in all its detail. Its extremely spatial - I’m thinking in 3D even if I’m not visualising it.
On the visual side, sometimes if I try hard I can make out an amorphous blob. Mostly colourless, though sometimes it has some abstract colours. Trying to recall actual detailed features is very hard, especially faces.
Occasionally I get memory flashes which are more like actually seeing a photograph in my head, but they last a fraction of a second and can’t be done on demand. Sometimes I have dreams which are more visual. This is how I know that my normal way of thinking isn’t visual.
A simple test I've seen mentioned is, ask someone this: “imagine a car, a fast car, zipping through a windy road… ok? (pause) now, what color was the car you saw?”
If you even need to think about it, you hadn't seen it.