Great, agree with your initial ID. Great colour changes for this genus depending on which elements they pick up in the soil. Have you ever found the white one?
Hmmm. Don't know. Just looking through my fungal photos and there is something similar in white. No idea what it is. Doesn't seem to fit any of the photos in the slime mould group.
And I am not familiar enough with slime moulds to know whether the things I am looking at are fungi or slime moulds. Hence they tend to lumped in as fungi until I find otherwise.