Shortly after Aether Revolt was first released, people started experimenting with decks featuring Hardened Scales and Winding Constrictor. Because of the combination of Arcbound Ravager and Steel Overseer, many of these decks ended up being pseudo-affinity decks, featuring many of the same cards, but with Hardened Scales in place of Cranial Plating. It's been awhile since we've seen any performances from that style of deck, but recently it appears to be on the rise again:

Hardened Scales Affinity - Modern | Hemsley, 5-0 Modern League

• Creatures (21)
• 1 Sparring Construct
• 4 Arcbound Ravager
• 4 Arcbound Worker
• 4 Hangarback Walker
• 4 Steel Overseer
• 4 Walking Ballista

• Instants (1)
• 1 Apostle's Blessing

• Sorceries (4)
• 4 Ancient Stirrings

• Enchantments (4)
• 4 Hardened Scales

• Artifacts (10)
• 1 Animation Module
• 2 Throne of Geth
• 3 Welding Jar
• 4 Mox Opal

• Lands (20)
• 7 Forest
• 1 Pendelhaven
• 2 Blinkmoth Nexus
• 2 Horizon Canopy
• 4 Darksteel Citadel
• 4 Inkmoth Nexus

• Sideboard (15)
• 2 Animation Module
• 4 Damping Sphere
• 2 Dismember
• 1 Gut Shot
• 4 Nature's Claim
• 2 Surgical Extraction

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Throne of Geth and Hardened Scales are sort of emblematic of the kinds of things that this deck is trying to do. You'd like to have a fast start with Darksteel Citadel and Mox Opal. This lets you get early combinations of Steel Overseer or Arcbound Ravager plus a Hangarback Walker or Walking Ballista. Much like typical Affinity decks, the power of each of your cards compounds the more of them you have in play. Steel Overseer gets better when you have multiple creatures that care about +1/+1 counters. Throne of Geth gets better when you're proliferating onto multiple cards or getting multiple counters off of Hardened Scales.

The terrifying piece of this deck is the combat math, particularly when combinations of Arcbound Ravager and Hardened Scales are involved. When each artifact is potentially two extra power on something like a Walking Ballista or an Inkmoth Nexus, you can kill opponents out of nowhere. That said, you have to do your math very carefully and play around whatever you can, because if you go all-in in the wrong places or mess up your math by a point, you'll lose games that you shouldn't have.