Rescue Persons of Interest and Prisoners of War in Metal Gear Solid 5: Ground Zeroes and upload that saved game file. Download that saved game file from the main menu in Metal Gear Solid 5: The Phantom Pain to obtain numerous benefits. Individuals you saved will appear at Mother Base as one of your benefits. Individuals that will appear are as follows.

Assassin Harrier: Appears affter two of either Missions 7, 8, or 9.
Bitter Centipede: Appears following Mission 12.
Blue Chameleon: Appears following Mission 6.
Crying Sturgeon: Appears after two of either Missions 7, 8, or 9.
Eye: Appears following Mission 6.
Finger: Appears following Mission 6.
Frigid Mongoose: Appears after two of either Missions 7, 8, or 9.
Gray Wallaby: Appears following Mission 6.
Grizzly Hedgehog: Appears following Missions 3, 4, and 5.
Hideo: Diplomat who appears following Missions 3, 4, and 5.
Hungry Crocodile: Appears following Missions 3, 4, and 5.
Hunting Stallion: Appears after two of either Missions 7, 8, or 9.
Mad Wallaby: Appears after two of either Missions 7, 8, or 9.
Midnight Mastiff: Appears following Mission 6.
Night Tree Frog: Appears following Mission 12.
Ochre Chameleon: Appears following Missions 3, 4, and 5.
Pirate Capybara: Appears following Mission 12.
Roaring Capybara: Appears following Mission 12.
Wild Harrier: Appears following Missions 3, 4, and 5.
Wild Stallion: Appears after two of either Missions 7, 8, or 9.