Here is the full list of all 38 Danganronpa S: Ultimate Summer Camp achievements.
Develop 1 character
Unlock the second island for the first time
Clear Welcome to Jabberwock Island
Unlock all achievements
Develop 10 characters or more and clear Monokid's Hope
Develop 20 characters or more and clear Monosuke's Hope
Develop 30 characters or more and clear Monodam's Hope
Develop 40 characters or more and clear Monophanie's Hope
Develop 50 characters or more and clear Monotaro's Hope
Clear Graduation
Clear Re:Welcome to Jabberwock Island
Clear the epilogue
Obtain all Danganronpa Character Cards
Obtain all Danganronpa 2 Character Cards
Obtain all Ultra Despair Girls Character Cards
Obtain all Danganronpa V3 Character Cards
Obtain all Character Cards
Obtain all Presents
Clear Floor 10 in Battle Mode
Clear Floor 100 in Battle Mode
Clear Floor 150 in Battle Mode
Clear Floor 200 in Battle Mode
Craft 1 equipment in Battle Mode
Equip all party members in Battle Mode
Craft all equipment in Battle Mode
Craft all weapons in Battle Mode
Craft all Ultimate Proofs
Unlock the third island for the first time
Unlock the fourth island for the first time
Unlock the fifth island for the first time
Defeat Monobeast (Human) in Development Mode for the first time
Obtain password for the first time
Defeat secret boss for the first time
Spin the MonoMono Machine 10 times
Spin the MonoMono Yachine 10 times
Spin the Golden MonoMono Machine 10 times
View all of a character's events
View all of every character's events