Let's go for a weird one here.
Status in da hood
EV:252 Spe 252 att
Fire Punch/Thunder Punch/Ice Punch
Fire Punch/Thunder Punch/Ice Punch
This set will let Scrafty take advantage of the fact that scrafty can learn so many moves that dole out status ailments. Rock Climb for confusion, Poison Jab for poisoning, Thunder punch for paralyzing, Fire Punch for burning, and Ice Punch for freezing. Throw in the expert belt for taking type advantages. The speed EVs for geting the move out first, and the attack EVs for doing maximum damage.
I can't tell if this is really a good option for Scrafty, it's more gimicky than anything.
Gimmicky indeed. Would be very promising on a Serene Grace Pokémon though. But it gave me an idea for a different gimmicky Scrafty set:
Impish (Def>SpA) or Careful (SpD>SpA)
EV: 252 Def | 252 SpD | 6 HP
~ Drain Punch
~ Toxic/Bulk Up/Dragon Dance
~ Dragon Tail
What this Scrafty attempts to do is annoy slash surprise the heck out of the opponent. When Scrafty shows up, the opponent will expect it to start attacking or boosting. Instead, you use Substitute. Scrafty's HP is nothing special, but with the max investment into both defences, you should be able to hide behind it for a while at least. Then you follow with Toxic (unless you're facing a Poison or Steel type obviously) or start boosting with Bulk Up or Dragon Dance. I think Bulk Up is better since it helps your Subs, but boosted Speed might be very useful too, especially for when your Sub breaks and you need to quickly set up another. Dragon Tail (remember it has decreased priority, so your Dragon Dances don't make it any faster) is here to switch out more dangerous opponents. This includes Ghost types you can't otherwise hit and Pokémon with Infiltrator. It's even better if you've set some hazards beforehand. Your Substitute will get broken eventually, but Leftovers keep you healed and you're using Drain Punch also. Shed Skin can heal you if you got statused before setting the Sub or by an Infiltrator Pokémon (like Will-O-Wisp Chandelure), but Intimidate helps you set up at the beginning.
Well, Fairies are still the bane of your existence. Can't switch them out with Dragon Tail and they resist Drain Punch, while destroying your Substitute in a milisecond. Don't
stay on Fairies, though Toxic them before running away if you can.
Infiltrator Pokémon are very dangerous starting this generation too and most of them can destroy you easily, either by status (like the aforementioned Will-O-Wisp Chandelure ruining your recovery and the already little damage you're dealing) or just hitting with super-effective moves (Crobat, Whimsicott, Noivern, even Superpower Malamar, though why it doesn't have Contrary is beyond me).
Watch out for Taunt, though before the surprised opponent thinks about Taunting you, you'll probably have a Substitute up and some boost or Toxics behind you.
Also ― your speed. Unless you managed to boost enough with Dragon Dance, you probably won't get a chance to set the second one before the opponent hits you. The best thing you can do then is predict well and use Substitute the very same turn your opponent destroys your first one.
Finally, the first turn is sink or swim for this Scrafty. If the opponent hits you bad enough right away, you might not even be able to set one Substitute, though with maxed Bulk and those stats, this really shouldn't happen outside of SE hits in which case why are you sending out Scrafty. You might start out by tricking your opponent into thinking you're using the usual offensive Scrafty, by boosting before
setting the sub, but don't blame me if you get statused while doing this.
Well, this set doesn't really allow for much variety. You need Substitute, that's the whole point, and Drain Punch keeps you healed. Dragon Tail is also a necessity because Ghosts if nothing else. You can replace your Toxic/Bulk Up/Dragon Dance slot with Swagger if you're feeling lucky, I guess.
What you'd love to have when using this set, is some hazards set on your foe's side of the battlefield. Every Dragon Tail will hurt much more that way. Also, you need something good against those pesky Fairies ― a Poison type is a good idea, since they also resist Fighting types (Electric/Poison or Steel/Poison or Rock/Poison would be perfect for resisting Flying too oh wait those still don't freakin' exist). I guess Crobat would make a good partner for this Scrafty ― fast, hitting Fairies and Fighters hard…