It’s still in Beta, and it doesn’t work properly yet, but from what I see it’s a very nice feature.
After opening Collections (Shift-C), click the Stable-masters tab. It’s pictured by… a cat… Guess that will be a mount when the update goes live, but this is LotRO, you never know.
On the tab you will see a map with all stables (3). Green (or yellow, help me oh editor, for I am colorblind) for the discovered stables, and black for the undiscovered. Handy, I found out there are two stables I am still missing, I thought I had all. You can see how many locations you have discovered in the bar on top (2).
Only the stables that fit the discription will stay visible. When you hover over a dot, the name will show up, and when you click the dot it will highlight. On the left you then see the name, whether you discovered the stable or not, a botton to travel, and a button to show the stable on the map.
These buttons don’t work in Beta yet. The travel must be paid with mithril coins. I hope this will change, but I think it won’t. A boy can dream though.
You can also type part of the name in the search box. All stables with the typed part in their name will show up. For example, type ‘os‘ and Ost Guruth will show up, but also Lhan Rhos.All in all, like I said, it looks promising.