Steel Division 2 is here, but GOG seems to be missing the first game, Steel Division: Normandy 44.

Seems like that indeed. Thank you!

Added:
Steel Division: Normandy 44

Risk of Rain 2 has just exited Early Access.

It has indeed, thank you!

Added:
Risk of Rain 2

The Dark Eye / Das Schwarze Auge universe:
The Dark Eye: Book of Heroes (store.steampowered.com/app/1139870/The_Dark_Eye__Book_of_Heroes/)

Warhammer Fantasy games:
Dungeonbowl Knockout Edition (store.steampowered.com/newshub/app/209390)/view/3150762393106745511
Warhammer: End Times – Vermintide (store.steampowered.com/app/235540)/Warhammer_End_Times__Vermintide/
Warhammer: Vermintide II (store.steampowered.com/app/552500/Warhammer_Vermintide_2/)
Warhammer Quest 2: The End Times (store.steampowered.com/app/910450/Warhammer_Quest_2_The_End_Times/)
Warhammer: Chaos & Conquest (store.steampowered.com/app/1144170/Warhammer_Chaos_And_Conquest/)
Warhammer Age of Sigmar: Champions (store.steampowered.com/app/988480/Warhammer_Age_of_Sigmar_Champions/)
Warhammer Underworlds: Online (store.steampowered.com/app/1022310/Warhammer_Underworlds_Online/)

Warhammer 40,000 games:
The Horus Heresy: Legions (store.steampowered.com/app/1031140/The_Horus_Heresy_Legions/)
The Horus Heresy: Battle of Tallarn (store.steampowered.com/news/?appgroupname=The+Horus+Heresy%3A+Battle+for+Tallarn&appids=515980)
The Horus Heresy: Betrayal at Calth (store.steampowered.com/app/556550/The_Horus_Heresy_Betrayal_at_Calth/)
Legacy of Dorn: Herald of Oblivion (store.steampowered.com/newshub/app/389850/view/2381789144747623979)
Warhammer 40,000: Eternal Crusade (store.steampowered.com/app/375230)/Warhammer_40000_Eternal_Crusade/)
Warhammer 40,000: Inquisitor - Martyr (store.steampowered.com/app/527430/Warhammer_40000_Inquisitor__Martyr/)
Warhammer 40,000: Inquisitor - Prophecy (store.steampowered.com/app/1042800/Warhammer_40000_Inquisitor__Prophecy/)
Aeronautica Imperialis: Flight Command (store.steampowered.com/app/610160/Aeronautica_Imperialis_Flight_Command/)
Adeptus Titanicus: Dominus (store.steampowered.com/app/853140/Adeptus_Titanicus_Dominus/)
Warhammer 40,000: Darktide (store.steampowered.com/app/1361210/Warhammer_40000_Darktide/)
Necromunda: Underhive Wars (store.steampowered.com/app/566440/Necromunda_Underhive_Wars/)
Space Hulk: Tactics (store.steampowered.com/app/492230/Space_Hulk_Tactics/)

STAR WARS games:
Star Wars: Squadrons (store.steampowered.com/app/1222730/STAR_WARS_Squadrons/)
Disney Infinity 3.0: Gold Edition (store.steampowered.com/app/541670/Disney_Infinity_30_Gold_Edition/)
Pinball FX3 - Star Wars Pinball (store.steampowered.com/app/646664/Pinball_FX3__Star_Wars_Pinball/)
Star Wars: Droid Repair Bay (store.steampowered.com/app/726910/Star_Wars_Droid_Repair_Bay/)
Star Wars: Imperial Assault - Legends of the Alliance (store.steampowered.com/app/703980/Star_Wars_Imperial_Assault__Legends_of_the_Alliance/)
Trials on Tatooine (store.steampowered.com/app/381940/Trials_on_Tatooine/)

Licensed LEGO titles:
LEGO Star Wars: The Skywalker Saga (store.steampowered.com/app/920210/LEGO_Star_Wars_The_Skywalker_Saga/)

Might and Magic series:
Might & Magic Heroes Online (store.steampowered.com/app/336520/Might__Magic_Heroes_Online/)
Might & Magic: Chess Royale (www.epicgames.com/store/en-US/product/might-and-magic-chess-royale/home)

Tomb Raider series:
Tomb Raider - The Final Hours Digital Book (store.steampowered.com/app/233410/Tomb_Raider__The_Final_Hours_Digital_Book/)

Alien(s) games and Predator games:
Pinball FX3 - Aliens vs Pinball (store.steampowered.com/app/646670/Pinball_FX3__Aliens_vs_Pinball/)

Middle-earth games:
Guardians of Middle-earth (store.steampowered.com/app/111900/Guardians_of_Middleearth/)
Middle-earth: Shadow of Mordor (store.steampowered.com/app/241930/Middleearth_Shadow_of_Mordor/)
Middle-earth: Shadow of War (store.steampowered.com/app/356190/Middleearth_Shadow_of_War/)
The Lord of the Rings: Journeys in Middle-earth (store.steampowered.com/app/1003400/The_Lord_of_the_Rings_Journeys_in_Middleearth/)
The Lord of the Rings: War in the North (store.steampowered.com/app/32800/Lord_of_the_Rings_War_in_the_North/)

Dungeons & Dragons games:
Dungeons & Dragons: Chronicles of Mystara (store.steampowered.com/app/229480/Dungeons__Dragons_Chronicles_of_Mystara/)
Idle Champions of the Forgotten Realms (store.steampowered.com/app/627690/Idle_Champions_of_the_Forgotten_Realms/)
Sword Coast Legends (store.steampowered.com/news/18911/)
Tales from Candlekeep: Tomb of Annihilation (store.steampowered.com/app/663380/Tales_from_Candlekeep_Tomb_of_Annihilation/)

Arcanum series:
Arcanum: The Lost Dungeon of Souls is part of The Arcanum Unofficial Patch (forum discussion), so technically is available.
www.gog.com/forum/arcanum_of_steamworks_and_magick_obscura/arcanum_unoffical_patch_15_released
terra-arcanum.com/drog/uap.html

Thank you!

Some entries you linked has been exluded for being online or MP-only, others has been exluded for not being released yet. Also skipped over some others that's not fitting (VR-only, DLCs to games that aren't here, companion apps etc.). I also skipped over the Middle-Earth games since afaik there are no LOTR-related games on GOG, but if I am wrong please point this out. One of the entries were already on the list (the Arcanum module).

Added:
The Dark Eye: Book of Heroes
Warhammer Quest 2: The End Times
The Horus Heresy: Battle of Tallarn
The Horus Heresy: Betrayal At Calth
Legacy of Dorn: Herald of Oblivion
Warhammer 40,000: Inquisitor - Martyr
Aeronautica Imperialis: Flight Command
Adeptus Titanicus: Dominus
Space Hulk: Tactics
Disney Infinity 3.0: Gold Edition
Dungeons & Dragons: Chronicles of Mystara
Idle Champions of the Forgotten Realms
Sword Coast Legends
Tales from Candlekeep: Tomb of Annihilation

I meant to say that Arcanum module probably shouldn't be on the list since can be legally obtained outside of GOG.

I get your point, but I'll still keep it for now because we do prefer to keep everything on GOG right? ;)

Some more D&D games:

Birthright: The Gorgon's Alliance (en.wikipedia.org/wiki/Birthright:_The_Gorgon%27s_Alliance)
Blood & Magic (en.wikipedia.org/wiki/Blood_%26_Magic)
Descent to Undermountain (en.wikipedia.org/wiki/Descent_to_Undermountain)
Dungeons & Dragons: Daggerdale (store.steampowered.com/app/99100/Dungeons_and_Dragons_Daggerdale/)
Fantasy Empires (en.wikipedia.org/wiki/Fantasy_Empires)
DeathKeep (en.wikipedia.org/wiki/DeathKeep)
Iron & Blood: Warriors of Ravenloft (en.wikipedia.org/wiki/Iron_%26_Blood:_Warriors_of_Ravenloft)
Spelljammer: Pirates of Realmspace (en.wikipedia.org/wiki/Spelljammer:_Pirates_of_Realmspace)

Also, Dragonlance is one of D&D settings, so it should not be separate group. Alternatively, you can split D&D group into settings like this:

Dungeons & Dragons: Birthright games:
Birthright: The Gorgon's Alliance
Dungeons & Dragons: Dragonlance games:
Dragons of Flame
DragonStrike
Heroes of the Lance
Shadow Sorcerer
War of the Lance
Dungeons & Dragons: Forgotten Realms games:
Sword Coast Legends
Idle Champions of the Forgotten Realms
Tales from Candlekeep: Tomb of Annihilation
Blood & Magic
Descent to Undermountain
Dungeons & Dragons: Daggerdale
Dungeons & Dragons: Mystara games:
Dungeons & Dragons: Chronicles of Mystara
Fantasy Empires
Dungeons & Dragons: Ravenloft games:
Iron & Blood: Warriors of Ravenloft
Dungeons & Dragons: Spelljammer games:
Spelljammer: Pirates of Realmspace
Dungeons & Dragons (no setting) games:
DeathKeep

Finally, it's worth noting that Chronicles of Mystara is compilation of two games: Shadow over Mystara and Tower of Doom.

Super Neptunia RPG was released one year ago on Steam:
https://store.steampowered.com/app/1016960/Super_Neptunia_RPG/

Thank you! I'll definitely use the DnD order that you put up, definitely more accessible that way :)

Thank you!

Added:
Birthright: The Gorgon's Alliance
Blood & Magic
Descent to Undermountain
Dungeons & Dragons: Daggerdale
Fantasy Empires
DeathKeep
Iron & Blood: Warriors of Ravenloft
Spelljammer: Pirates of Realmspace
Super Neptunia RPG
Crusader Kings III

One more:

Ultima games:
Underworld Ascendant

Thank you!

Also added the remaining titles from the Merchant Prince series as Machiavelli: The Prince was added to the catalogue today.

Added:
Underworld Ascendant
Merchant Prince
Merchant Prince II

Added:
Metal Gear Rising: Revengeance
Metal Gear Solid V: Ground Zeroes
Metal Gear Solid V: The Phantom Pain
Haunted Castle (as part of Anniversary Collection Arcade Classics)
Super Castlevania IV (as part of Castlevania Anniversary Collection)
Castlevania The Adventure (as part of Castlevania Anniversary Collection)
Castlevania II Belmont's Revenge (as part of Castlevania Anniversary Collection)
Castlevania Bloodlines (as part of Castlevania Anniversary Collection)
Kid Dracula (as part of Castlevania Anniversary Collection)
Castlevania: Lords of Shadow
Castlevania: Lords of Shadow – Mirror of Fate
Castlevania: Lords of Shadow 2
Contra III: The Alien Wars (as part of Contra Anniversary Collection)
Operation C (as part of Contra Anniversary Collection)
Contra Hard Corps (as part of Contra Anniversary Collection)
Contra: Rogue Corps

Since the Anniversary Collections have better emulation as well access to alternative versions, I'd recommend you just consolidate all the entries above into their three respective entries.



In other news, Mafia: Definitive Edition was released today on Steam.