Here is the full list of all 28 Vellum achievements.
Mend your first Tome.
Mend 5 Tomes.
Mend 10 Tomes.
Mend the Illegible Tome.
Mend a Tome in less than 10 minutes.
Mend a Tome at Binding Level 1.
Mend a Tome at Binding Level 5.
Mend a Tome at Binding Level 10.
Mend a Tome at Binding Level 15.
Mend a Tome at Binding Level 20.
Defeat a Boss with the Shredded Pages Binding active.
Defeat a Boss with the Broken Spines Binding active.
Flourish for more than 3000 Damage.
Heal 10,000 Health in a Single Run.
Deal 20,000 Inkling Damage in a single run.
Deal 30,000 Status Damage in a single run.
Reach Ink Level 2.
Reach Ink Level 10.
Reach Ink Level 30.
Unlock 5 Spells, 4 Signature Inks, and reach Ink Level 30.
Unlock a new Spell.
Unlock 5 Spells.
Unlock a new Signature Ink.
Unlock 4 Signature Inks
Defeat a Torn Boss at Appendix 1 during an Endless Run
Defeat a Torn Boss at Appendix 3 during an Endless Run
Ascend for the first time.
Ascend twice.