I maintain a growing list of OST's for my own listening enjoyment but also for speaker testing because it can be great material for that due to the general high quality. Here is not a complete list, but the most notable ones I have. I'm always looking for more so I'll go through this thread when I have time and see what every one else is noting.
Amanchu! Original Soundtrack
Aquaman
Avengers:
Infinity War
Endgame
Batman:
The Dark Knight
The Dark Knight Rises
Bethesda Softworks:
The Elder Scrolls III, IV, Online, Skyrim
Bioware
Dragon Age - Origins
Dragon Age - Inquisition
Dragon Age II
Mass Effect
Mass Effect II (and all DLC)
Mass Effect III (and all DLC)
Mass Effect Andromeda
Black Panther
Blade Runner 2049
Blizzard Entertainment:
All Diablo, Warcraft, and Starcraft from 1994-2016
Crytek:
Crysis 1, 2, 3
Edge of Tomorrow
Epic Games:
Gears of War 1, 2, 3
Unreal Tournament, 2004, and III
Gladiator: Complete Score
Harry Potter:
The Philosopher's Stone
Chamber of Secrets
Prisoner of Azkaban
Goblet of Fire
Order of the Phoenix
Half-Blood Prince
Inception
Justice League
Mission Impossible: Fallout
Blue Dragon OST
Oblivion OST
Pirates of the Caribbean:
The Curse of the Black Pearl
Dead Man's Chest
At World's End
On Stranger Tides
Dead Men Tell No Tales
Ready Player One
Sony:
God of War I, II, III, Ascension
Horizon Zero Dawn
Uncharted 1, 2, 3, 4
Square Enix:
Final Fantasy VI, VII, VIII, IX, X, X-2, X-2 Piano Collection, XII, XIII, XV, XV Piano Arrangement
Squaresoft:
Chrono Trigger
Chrono Cross
Chrono Symphonic
Secret of Evermore
Secret of Mana
Star Trek:
Into Darkness
Beyond
Discovery
Star Wars:
The Force Awakens
Rogue One
The Last Jedi
Solo
The Legend of Zelda: Breath of the Wild
The Lord Of The Rings Trilogy
The Nightmare Before Christmas
The Witcher 3: Wild Hunt
Transformers:
Transformers
Revenge Of The Fallen
Dark of the Moon
Age Of Extinction
The Last Knight
TRON Legacy Soundtrack
Walt Disney: Fantasia
War for the Planet of the Apes
Wonder Woman