Here is the full list of all 17 Monstronomy achievements.
Collect your first starter Monster.
Evolve a monster.
Catch a monster.
Join with Skelling and Caleb to stop the Cultists.
Access the basement of Skelling's Lab.
Side with Blue Ship Industries.
Side with Caleb.
Defeat Vladmir at the Cathedral.
Watch all videos.
Defeat the E14.
Catch every Abomination.
Escape the void knife scene.
Use a status effect move.
Catch every monster.
Complete the Monsterpedia.
Beat Boca Broomer in under 5 minutes.
Learn about Corrupted Monsters.