Encounter one of the following monsters to unlock the corresponding movie in the gallery:

MONSTER - MOVIE
Avian Master of Jungle - Yian Kut Ku in the "Great Jungle Kut Ku" quest
Blue Hunter - Velociprey in "Your First Monster Hunt" quest
Divine Providence - Rathalos in the "Rathalos Urgent" quest
King of the Heavens - Rathalos in the "One Star Egg Carry" quest
Lao-Shan Lung - Lao Shan Lung
Menace in the Sand - Cephladrome in the "Land Shark" quest
Poison of the Swamp - Gypceros in the swamp
Shepard - Velocidrome in the "The Formidable Velocidrome!" quest
Supreme Ruler Inferno - Gravios
The Lone Black Wolf - Yian Garuga in the "Slay 20 Velociprey" quest
The Phantom Beast - Kirin
The Ancient Piscine - Plesioth