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