Here is the full list of all 35 Desta: The Memories Between achievements.
Recruit Fran for the first time
Recruit James for the first time
Recruit Miss K for the first time
Recruit Sun for the first time
Recruit Lee for the first time
Recruit Nila for the first time
Recruit Devòn for the first time
Recruit Yusuf for the first time
Recruit Alba for the first time
Have an honest conversation with mum
Win a match with Fran and James on the same team
Win a match with Lee and James on the same team
Win a match with Sun and Nila on the same team
Win a match with Yusuf and Miss K on the same team
Win a match with Sun and Miss K on the same team
Win a match with Lee and Fran on the same team
Win a match with Yusuf and Nila on the same team
Win a match with Alba and James on the same team
Win a match with Devòn and Miss K on the same team
Fully level up Nila
Fully level up Lee
Fully level up Sun
Fully level up Miss K
Fully level up James
Fully level up Fran
Fully level up Yusuf
Fully level up Devòn
Master Every Ability
Fully level up Alba
Defeat two opponents with one throw
Damage three opponents with one throw
Catch a rebound after throwing
Do a throw that takes away 4+HP from an opponent
Finish the game in Nightmare mode
Make a Hype Raver KO another Opponent