Assume you bought a game on steam and 7 out of 10 DLCs that are available for that game. When you go (in the steam application) to "LIBRARY" -> "game XY" -> "DLC", you get a list of all DLCs that are available for the game XY but none of the DLCs are marked as bought or not… (?!) At least I don't see any marks. If you click on a specific DLC though, you get "You already own XY", or the "Buy XY" depending on having/not having the DLC.
Is there an easier way to find out which DLCs you are missing than clicking to each DLC? Perhaps a place (that I haven't found yet) with a list of all the DLCs available for that game and some small icons that would tell you if you have that DLC or not?
I am asking because if a game has lots of DLCs, it is a bit tiresome to click and check all of them.
Best Answer
As of the Steam Discovery Update on Sept. 23rd, 2014, Steam itself now shows you the DLC you own in the Store page without having to use browser extensions or look at the game properties in your library.
The blue markings on the left side of each DLC entry indicate that I own it already and if I hover over it, there will be a popout that shows that it's in my library.
Note that isn't perfect. In this particular example, Steam shows that I don't own Wonders of the Ancient World, even though I do, but I'm guessing that's a problem with that particular piece of DLC, as it's done that since release. However, Steam still won't let you buy anything you already own, so you're safe from double purchases.