Here is the full list of all 47 ECHO achievements.
Shout and get the attention of 8 Echoes at once
Kill 3 Echoes by shooting a Sun
Traverse infinity for a while
Look at yourself in the mirror excessively
Complete the fifth Verse
Use Area Scan 20 times
Have Echoes know how to sprint, vault, use doors and walk in water at the same time
Pick up every orb in every caste level
Collect all Voices
Line up and shoot 6 Echoes with a single shot
Throw 20 Crystal Balls
Finish the game on Ultra Hard
Complete the fourth Verse
Collect 100 Voices
Complete the third Verse
Have Echoes play the harp and piano at the same time.
Play the whole piano piece during a blackout
Complete the second Verse
Tag 100 Echoes
Complete the first Verse
Push 5 Echoes at once with the Riot Gun
Shoot 200 Echoes
Collect 50 Voices
Finish the game on any difficulty
Take out a Hyper Echo
Collect a Voice by having an Echo strike it
Reach Chapter VI
Get 4 additional Cell capacity slots
Distract 5 Echoes at once with one Crystal Ball
Get Foster back
Reach Chapter V
Take out 47 Echoes with the stealth takedown
Collect 25 Voices
Push an Echo over a railing
Eat 20 pieces of fruit
Pick up 50 Suns
Make a 2 cell energy drop during a blackout
Kill 10 Echoes with Crystal Balls
Eat 5 pieces of fruit during a single blackout
Get 2 additional Cell capacity slot
Reach Chapter IV
Push 50 Echoes
Collect 10 Voices
Get an additional Cell capacity slot
Reach Chapter III
Line up and shoot 3 Echoes with a single shot
Activate the palace