Here is the full list of all 30 The Legend of Korra achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Completed the game on Extreme difficulty.
Used your first equipped item.
Purchased 12 talismans.
Collected every treasure item.
Countered 100 times.
Performed 100 Finishing Moves.
Spirit-bended 200 dark spirits.
Went into Avatar State 10 times.
Got 10 Knockouts in Pro-bending matches.
Won a Face-Off in a Pro-bending match.
Completed the highest difficulty of Pro-bending.
Completed all tutorials.
Collected 10 cabbages.
Dodged 100 times.
Entered the Collection Screen for the first time after finding a treasure.
Completed Chapter 8.
Maxed out all bending types.
Obtained all combos.
Completed Chapter 7.
Went into Clash Mode 10 times.
Completed Chapter 6.
Completed Chapter 5.
Completed Chapter 4.
Completed a Naga Running sequence without hitting anything.
Jumped 100 times.
Equip your first item in Korra's Room.
Bought your first item at the shop.
Completed Chapter 3.
Completed Chapter 2.
Completed Chapter 1.