HI @drmudlark,
I’m attaching a screen shot of the categories sections so you can let us know if you see the same! Even with the category organisation here, they are quite broad (categories such as sleeplessness, anxiety, and sofi as a whole, etc). You will see the most popular threads/topics on the right hand side, however, which can be a big help.
On a phone the categories option is a dropdown you can select by first clicking on"Latest"
Then, in line with your suggestion, I’m keen to improve our Indexing system. Could you confirm for me whether or not you see this Index at the top of your page? It is currently pinned for me, but I believe individuals have the option to get rid of it.
We do include a post here related to the pebbles, but we currently don’t group all the photos + individual posts under this heading as you say. I’d love to hear what else might be the most valuable to include here 
Love these discussions and the growth and range of improvements that arise from them - so really grateful for your time! x