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