One of the breakout performers for a fleetingly short period of time in last year’s Standard format was G/W Hardened Scales. This little 1-mana enchantment was a game-changer as more and more effects that added counters to creatures saw print.
Hardened Scales turns all of your cheap ways to add counters to your creatures into powerhouses. What sounds like a nominal advantage, a single extra +1/+1 counter, can become overwhelming when it’s either repeatable or extremely cheap. Scales has rotated out of Standard, but Frontier could have access to another version of the effect, thanks to the recently spoiled Aether Revolt card Winding Constrictor.
Servant of the Scale is an anemic threat, even in Limited. A 1/1 for 1 with upside isn’t unplayable, but it’s also not exactly desirable. A single Hardened Scales turns your smallest creature into a 2/2 for 1 with a lot of upside. Putting what would now be 2 (or more) counters onto another creature, with ways to add even more counters—all of which are increased again by Hardened Scales—lets things spin completely out of control.
Avatar of the Resolute is one of the big payoffs for playing creatures with counters. You’re going to get a massive creature with trample for a mere 2 mana investment, and it even has reach (as many players fail to remember).
Hangarback Walker will enter with extra counters and pump for a pair of counters each turn with a Hardened Scales in play. Den Protector will provide extra value as it flips into a 4/3 creature with evasion. Tireless Tracker will grow out of control quickly while drawing extra cards.
Managorger Hydra becomes an enormous end-game, and will only cost you 3 mana to get started. A Hardened Scales in play means multiple counters for every spell. Keep in mind that you can cast Hangarback Walker for 0 mana just to put a couple counters on your Hydra if necessary.
Dromoka's Command is your big removal spell. For just 2 mana, you’re getting an instant that can put a counter on a creature (often 2 or more thanks to Scales), fight now smaller creatures, kill an enchantment, or stop some of the powerful burn available in Frontier.
Nissa, Voice of Zendikar does it all. She'll pump out an army of Plants before putting counters on your entire team. Combined with Scales, her -2 ability is tough to beat.
The top end is a brand new Kaladesh card that wasn’t an option for Hardened Scales until now. Verdurous Gearhulk is a massive threat that can spread counters around to your team while also providing a large trampling creature. With Hardened Scales in play, Gearhulk functions as a pseudo-Overrun with legs that should end the game in a real hurry.
G/W Hardened Scales
Kaneko Junpei, 4-1 in a Hareruya Frontier Daily