Thanks to those contributing to this thread and search. It's great fun following and participating myself.
It took me from Horizons launch until yesterday to afford a Cobra Mk3 outfitted with ADS, DDS, SRV, etc., capable of reaching The Pleiades. After working hard on those CGs for Obsidian Orbital, I'm quite excited to be able to see it in person and get to searching the area.
Regarding barnacles, I had been thinking that the volatile mists were somehow required, but I am finding precious few instances. Usually planets very near their star, which I presume is heating/releasing those volatile gases. Yesterday, I spent most of my time down in deep craters, looking for dark nooks and such. Why? Because of the atmosphere in the trailer video? Maybe.
But reading on barnacles, they are usually not deep dwellers, but reside in tidal areas. And often encrusting structures which are on the boundary of the water (volatile mist?) layer.
One of the photos I saw while researching barnacles reminded me exactly of this type of area:
View attachment 94527
The kind of place that looks like had been a flood plane, or frequently submerged, strewn with rocks and boulders, which the barnacles would encrust. I have not found such an area with mists, yet.
One other thought... I seem to recall reading that during the Horizons beta, there was a test CG where Roman Numerals were given as clues of a system to search. This came to mind when I observed upon Arrival in Maia, that Obsidian Orbital had been placed orbiting M(a)2A.