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