As most as complete list of co-op games I find - came across

List of games (what I found which have some form of campaign co-op or something similar, trying to have mix of different platforms and genres) 

Co-op hry – PC (Amd also possible console) 

Age Of Conan  

Aion  

ArchAge  

Anthem  

Ark – Survival Evolved 

The Ascent 

Avatar – Frontiers Of Pandora 

Alien Breed 1  

Alien Breed 2

Alien Breed 3

Alien Swarm  

Aliens – Colonial Marines 

Aliens – Fireteam Elite 

AvP 2 (Co-op mod) 

Aura Kingdom (Private servers) 

A Way Out  

Baldur´s Gate 1  

Baldur´s Gate – Dark Alliance,  

Baldur´s Gate - Dark Alliance (2021) 

Baldur´s Gate - Dark Alliance 2 

Beyond  Two Souls 

Blade & Soul 

Blazing Chrome 

Blood  

Blood Knight 

Borderlands+DLCs 

Borderlands 2+DLCs 

Borderland 3+DLCs 

Borderlands Pre-Sequel 

Brink 

BroForce  

Call Of Juarez – The Cartel 

Cars 2 

Cars 3 

Cat Quest 2 

Commandos+expansion  

Commandos 2  

C&C - Red Alert 3 

Contra 

Contra III 

Contra – Rogue Cops 

Crawlers and Brawlers co-op 

The Crew 2 

The Crew - Motosport  

Cronous Online 

Cry Of Fear (co-op režim) 

Damnation  

The Dark Anthology Pictures 

Darksburg 

Darksiders Genesis  

Dark Souls 2 

Dark Souls 3 

DC Universe Online 

Dauntless  

Dead Island 

Dead Island Riptide 

Dead Island 2 

Dead Island 2 

Dead Rising 2 

Dead Rising – Off the Records 

Dead Rising 3 

Dead Rising 4 

Death Squared 

Destiny 2  

Diablo 

Diablo 2 

Diablo 3 Reapers of Soul 

Diablo 4  

Diablo Immortal 

Doom (+extra episode)  

Doom 2 (+addons, mods) 

Dragon Nest (there should be private servers) 

Dungeon Defenders 

Dungeon Defenders 2 

Dungeon Defenders – Awakened 

Dungeons - The Eye of Draconis 

Dungeon Siege  - Throne Of Agony 

Dungeons & Dragons - Heroes 

Dungeons & Dragons – Chronicles Of Mystara  

Dungeons Of Sundaria  

Dying Light 

Dying Light 2 

Earth Defense Force 2017 

Earth Defense Force – Insect Armageddon 

Earth Defense Force 2025/Earth Defense Force 4.1 - New Despair 

Earth Defense Force 6 

Earth Defense Force – Iron Rain 

Eden Eternal 

Echo Of Souls  

Elden Ring 

The Elder Scroll Online  

The Elder Scroll Skyrim Co-op mod 

Eldevin 

Elyon 

Enter the Gungeon 

Everquest  

Everquest 2 

Evil West 

Expendable 

Extreme Exorcism 

Fallout 76 

Fortnite - Save The World 

Far Cry  

Far Cry 5 

Far Cry 6 

Fiesta Online 

Fight´n Rage 

The First Templar 

Florensia 

For the King 

Forced 

Forza Horizon 4 

Forza Horizon 5 

From Space 

Future Cop LAPD 

Godsworn 

Goat Simulator  

Goat Simulator 3 

Global Defense Force 

Grim Dawn  

Helldrivers 1  

Helldrivers 2  

Herectic  

Hexen 

Hexen 2+expansion 

Hero Siege 

Championship of Norrath  

Chenso Club 

Children of Morta  

Chimeraland 

The Chronicles Of Spellborn 

Icewind Dale  

Icewnd Dale 2 

Incredible Adventure Of Van Helsing 

Incredible Adventure Of Van Helsing 2 

Incredible Adventure Of Van Helsing 3 

Kane & Lynch 

Kane & Lynch 2 

Kebab Restaurant 

Left 4 Dead 2 

Lego games 

Lineage 2 

Lord Of The Rings Online 

The Lord Of the Rings - War In North

Lost Ark  

Marvel’ Avengers  

Marvel Ultimate Alliance   

Marvel Ultimate Alliance 2 

Meat Iron 

Minecraft Dungeons  

Moon Hunters  

Monster Attack   

Monster Hunter Tri  

Neverwinter (MMORPG) 

Neverwinter Nights  

New World 

No More Room In Hell 

Outbreak  

Quake 1 

Quake 2  

The Quarry 

Quest Hunter  

Payday 

Payday 2 

Payday 3 

Remnant  

Remnant 2 

Rift  

Sacred Gold

Sacred 2  

Secret World  

Serious Sam HD - First Encounter 

Serious Sam HD – Second Encounter 

Serious Sam 3 

Serious Sam 4  

Serious Sam XXL  

Shadow Warrior  

Shatterline 

Space Hulk – Deathwing  

Star Trek Online (MMORPG) 

Star Trek - The Videogame 

State Of Decay 2 

Super Contra 

Synced  

System Shock 2  

The Cursed Crusade 

Tiny Tina´s Wonderlands (Borderland series) 

Titan Quest  

Tom Clancy’s Rainbow Six: Extraction 

Tom Clancy’s Rainbow Six: Rogue Spear 

Tom Clancy’s Rainbow Six 3: Raven Shield 

Tom Clancy’s Rainbow Six: Vegas 

Tom Clancy’s Rainbow Six: Vegas 2 

Trine 

Trine 2 

Trine 3 

Trine 4 

Tine 5 

Turok 2 

Warframe  

Warhammer 40000: Inquisitor  

Warhammer – Vermintide 2  

Wastelands 3  

Wizard Of Legends 

Wizard Of Legends 2 

World War Z  

 

Others (mainly their most famous platforms they were published/their only platform) 

Playstation  

Contra – Legacy Of War 

Gauntlet Legends  

  

Playstation 2 /Xbox 1 (OG) 

Darkwatch 

Mortal Kombat - Shaolin Monks  

The Sims 2 

The Sims Bustin' Out  

The Urbz: Sims in the City 

Timesplitters 

Timesplitters 2 

Timesplitters – Future Perfect 

  

Playstation 3/Xbox 360 

Army Of Two 

Army Of Two – 40th  

Army Of Two - Devil´s Carter 

Fuse  

Haze 

  

Xbox OG  

Black Stone – Magic & Steel  

Dungeons & Dragons Heroes  

Xbox 360

Crimson Alliance

  

Xbox 360/One/Series X  

Fable 2  

Fable 3 

OutWorld  

Perfect Dark 

Perfect Dark Zero  

Warhammer – Chaosbane 

NES 

Contra Forces 

 

Playstation 2 

Contra – Shattered Soldier 

Neo Contra 

 

Playstaton 3 

Haze 

LittleBigPlanet 1-3 

 

Nintedo DS 

Contra 4 

 

WiiWare 

Contra ReBirth 

 

Switch 

Marvel Ultimate Alliance 3 

 

Mega Drive/Genesis 

Contra – Hard Corps 

 

S otazníkem 

Dragon Saga 

Dream Of Mirror Online 

Entasy Online 

Expedition Agartha 

Fantasy Tales Online 

Hoard 

 

Nefunkční co-op hry/non-functional co-op games 

The Crew (nefunkční servery/servers shutdown) 

Forza Horizon 2 

Forza Horizon 3