I can look through the "Store" portion of Steam using tags, and I can also do an advanced-search on certain features like local co-op support. But for some reason, when I do this I can't tell which games I already own, and I don't seem to be able to do the same search / filter when viewing my library.
Am I missing an option somewhere? It seems like a no-brainer to be allowed to do this.
Best Answer
Some months ago I made a tool for this exact purpose.
You can filter your library or wishlist by any combination of one or more tags and features, and also sort by your playtime or Metascore. You're welcome :)