Here's one I haven't seen yet.
Flygon @ Expert Belt / Blunder Policy* / Life Orb
Ability: Levitate
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Dragon Dance
- Earthquake
- Superpower / Stone Edge
- coverage move (Fire Punch, First Impression, Dragon Rush if you're real brave)
Now there is definitely a reason Flygon wasn't listed, and I'm sure that reason is because it's not as good as these other ones, but it's still plenty capable of holding its own. I had a bit of a tough time thinking of the proper item for it. I almost Life Orbed it, but I'm not so sure I want a DDancer with an even further limited health pool. It's usable in OU, but can be a little bit of a risk if you don't know exactly what its problems are.
Flygon is kind of strange in that it is both predictable and not. Most every one of them you'll see has Dragon Dance now, but what it chooses to butcher its opponents with is not as clear beyond the staple Earthquake. I would recommend taking one of Superpower or Stone Edge to fend off Ice types. Superpower has more power overall, more reliable accuracy, the ability to delete Hydreigon, Tyranitar and Bisharp (if Earthquake isn't enough), and finally an unfortunate drop that you can handle thanks to Dragon Dance. However, it's not quite as well-covering as Stone Edge would be, which takes care of Flying-types and Rotom-Heat, which Flygon would struggle to deal with otherwise.
The final move is up to you. Fire Punch would remove Ferrothorn, First Impression can let you sneak a hit in if necessary, Dragon Rush is a strong move with poor accuracy but would help in defeating a Dracovish. If you want to run Dragon Rush on this set, that would be the time to use a Blunder Policy, as Dragon moves usually get poor coverage, defeating the purpose of the belt. Stone Edge also would benefit from the use of this item.
In all, Flygon's a wildcard that you could throw in to take care of specific threats your team struggles with. If you're using it in a tier above what it's designed for (OU as a UU mon), it struggles with Mamoswine with a 4x weakness to Ice Shard (yikes). Unaware Clefable will also not only wall Flygon but probably kill it before it can do sufficient damage.
EDIT: I also noticed Duraludon was not present beyond a passing mention in this thread.
Duraludon @ Choice Specs
Ability: Light Metal
EVs: 252 HP, 4 Def, 252 SpAtk
Nature: Modest
- Flash Cannon
- Draco Meteor
- Thunderbolt
- Dark Pulse
This moveset was posted on PokemonDB's Duraludon moveset thread by Soundwave.
Again, less viable than others provided, but still fairly powerful. Its main problem is that its movepool is very shallow, and thus is predictable, with the exception of Draco Meteor and Flash Cannon occasionally being replaced by Dragon Pulse and Steel Beam, respectively (though the latter is rare and usually appears with GMax sets). Other than that, pretty much every Duraludon carries either of those two STABs plus Dark Pulse and Thunderbolt.
What Duraludon can do, though, is function as a capable wallbreaking tank. It's not very fast, but it has excellent defensive typing as well, with weaknesses to only Ground and Fighting that it is more than capable of handling (see base 115 Defense). It is quite appropriately made out of metal, because it hits like a truck.
Now for something for clever, innovative, and pretty usable, although somewhat gimmicky:
Duraludon @ Blunder Policy
Ability: Light Metal
EVs: 80 HP / 252 SpA / 176 Spe
Modest Nature
IVs: 0 Atk
- Substitute
- Thunder
- Flash Cannon
- Draco Meteor
If you miss a Thunder or Draco Meteor, you activate the Blunder Policy and take advantage of Duraludon's 120 base special attack stat [while still being speedy].
Incidentally, this set was made by NebbyY, who originally made that passing mention of Duraludon. It is also posted on the PokemonDB Duraludon moveset thread.
If this edit brought you here and you like these, before you'd ever cast a vote for me, give them credit on that moveset thread instead!
(end shameless plug, sorry, I'd feel guilty for stealing if I didn't)