Augments
Augments are extra stat sticks that equip to your second mercenary slot and are not useable in PvP or BvB. They’re buyable in two tiers, Tier 1 (Crystal x Giga cost) and Tier 2 (Crystal x Coin cost). Augments greatly boost individual stats of your choosing, however they are only available in 1, 3 and 7 days - so they are very much a lategame crystal sink item.
Here are the available Augments -

VIT Augment
BOT type: Any
Item type: Mercenary
Req. Level: 0
Greatly increases your health for a period of time. [OC1]
HP
+2500

SPD Augment
BOT type: Any
Item type: Mercenary
Req. Level: 0
Greatly increases your speed for a period of time. [OC1]
Speed
+30

TA Augment
BOT type: Any
Item type: Mercenary
Req. Level: 0
Greatly increases your TA for a period of time. [OC1]
Trans Bot Attack
+550

TD Augment
BOT type: Any
Item type: Mercenary
Req. Level: 0
Greatly increases your TD for a period of time. [OC1]
Trans Bot Def
+300

CRT Augment
BOT type: Any
Item type: Mercenary
Req. Level: 0
Increase your critical while converting crit after 1,000 to bonus damage. [OC1]
Critical
+350

Luck Augment
BOT type: Any
Item type: Mercenary
Req. Level: 0
Increase your luck for a period of time. [OC1]
Luck
+125

Crystal Tracker
BOT type: Any
Item type: Mercenary
Req. Level: 0
Greatly increase LegendCrystal find chance for a short period of time. [OC1]
HP
+400
Permanent Augments
This augment takes the second merc slot and gives an array of powerful bonuses. Comes in two tiers, Tier 1 gives +10% EXP and other stats, Tier 2 gives +20% EXP and other stats.

Augment of Prosperity[T1]
BOT type: Any
Item type: Mercenary
Req. Level: 0
Can be purchased for 6,250 Coins
Permanent augment to increase XP, crystals and a variety of power-bolstering stats.
HP
+500
Transformation Gauge +50
Trans Bot Def +50
Ranged Attack +50
Luck +100
Transformation Gauge +50
Trans Bot Def +50
Ranged Attack +50
Luck +100

Augment of Prosperity[T2]
BOT type: Any
Item type: Mercenary
Req. Level: 0
Can be purchased for 6,250 Coins
Permanent augment to increase XP, crystals and a variety of power-bolstering stats.
HP
+1000
Transformation Gauge +100
Trans Bot Def +100
Ranged Attack +100
Luck +200
Transformation Gauge +100
Trans Bot Def +100
Ranged Attack +100
Luck +200