What is this place?
Essentially, it's a database of World of Warcraft gear that can be used by Warriors for transmogrification. There's a lot of armor here, but my focus is on WEAPONS and SHIELDS (I'm a warrior, what did you expect?) Here, I can focus on pieces usable by WARRIORS, rather than a general-purpose gallery. All of the armor pieces you'll find are Plate. The weapons are pieces that Warriors can use, and don't include things such as daggers, fist weapons, crossbows, and so on.
Why can't I find <insert favorite piece>?
Probably because I haven't looted it yet. Back when I started collecting transmog pieces, I decided that I would rely on screenshots of my warrior WEARING each piece rather than using a model viewer. While this lets me have more freedom with lighting/location/et cetera, it does mean that I have to actually possess a piece before I add it to the database. I've also limited myself to posting pieces that can be obtained solo, which eliminates *most* raid gear from MoP and WoD.
Why is the "Difficulty" field so inconsistent between pieces?
Because loot tables are WEIRD. In Vanilla WoW, any given instance had a single difficulty/size. In Burning Crusade, we saw dungeons that came in Normal and Heroic difficulties. Some items dropped on both difficulties, some on only one, but there's no real pattern. Wrath of the Lich King complicated matters further with raids that could be any combination of Normal/Heroic/10-man/25-man: some pieces would only drop on a specific raid SIZE, with color variations for Normal versus Heroic (ICC gear was like this). Some raids, like Trial of the Crusader, have some pieces without variants (shields) and some with variants (certain weapons, armor). Things got simpler in Cataclysm onward, with shared loot tables between raid sizes and color variations for difficulty levels (though some pieces, like Tier 11 weapons, only had one color palette). What I've tried to do is indicate all of the possible instance sizes and difficulties in which a given gear model + color Variant COULD appear. If a piece says "10-man, 25-man, Normal, Heroic", or nothing at all, it doesn't matter what version of the instance you're running.
tl;dr: WoW loot tables are wonky.