I've given up on ever finding where I've put content on my ancient runtime and basically use the Poser search function to locate what I need.

If I need a table or a wall or a gun for a scene I just do a search for it.

With the wisdom of hindsight I now place content in sub-folders that are easy to search for. Which is another great reason why you should never let the Daz installer dump directly into your runtime...you'll never ever find it again. For finding texture maps from the Material Room I use the Everything Search Engine (freeware) which IMO is better and more secure than Windows search and the indexing involved, but no thumbnails.