I will happily take this opportunity to complain

/startrant that the abandonment of couch co-op is the worst thing to ever happen to gaming. There are some great couch co-op games out there, BUT NOT NEARLY ENOUGH. Seriously, the number of goddamn games that expect you to HAVE TWO COMPUTER AND TWO SCREENS SO YOU CAN PLAY CO-OP WITH SOMEONE ELSE IS TOO DAMN HIGH. /endrant

I highly recommend Broforce, any of the Larian studio games (Divinity Original Sin, Baldur's Gate 3 etc..), Battleblock Theater, Castle Crashers, Cuphead, For The King, Hypercharge Unboxed, It Takes Two, Portal 2, Overcooked, SpiritFarer, Stardew Valley, Untitled Goose Game, Wobbly Life. Wish there were more.

It is the damndest shame that the Halo Master Chief Collection doesn't have local co-op, still upsets me to this day.

Some splitscreen multiplayer games I've played and enjoyed:

• It Takes Two - 2 player couch. Amazing game
• Octodad - 4p. Every player controls one or two limbs of an octopus, who needs to pretend to be a normal father
• Nom Nom Galaxy - 2 player couch, 4 player online. Land on an alien planet and build a soup factory. Collect ingredients and fight against another corporation.
• Crawl - 4p. One player is a hero running through a dungeon, the other players control monsters trying to kill them. Whoever kills the hero then becomes the hero. Whoever kills the boss first, wins. Great soundtrack and art.
• Stick Fight - 4p. Competitive yet silly ragdoll combat game
• Magicka 1 and 2 - 4p. Wizard game, create spells by mixing elements and blow up a bunch of goblins.
• Stikbold! - 4p. Dodgeball game, a decent bit of skill involved. Can fight each other or against AI.
• Tooth and Tail - 4p. An RTS game that works well on controllers, you control an army of woodland creatures and have to kill / eat the others. Great soundtrack and art. Can play PvP or against AI.
• Lovers in a Dangerous Spacetime - 4p. Work together to pilot a spaceship and kill monsters and save people.
• Guns, Gore & Cannoli - 4p. Arcadey shoot lots of zombies side scroller.
• Treadnauts - 4p. Fight each other by driving tanks on walls
• Ultimate Chicken Horse - 4p. Design a shared platforming level with traps, so that you're able to get to the end but the other players can't.
• All the Lego games - 2p.
• Stardew Valley - 4p. Grow a farm and befriend villagers
• Speedrunners - 4p. Just run and do parkour faster than the other players
• the Trine games - 3p. Cooperative adventure / puzzle game.
• Wizard of Legend - 2p. Wizard roguelike
• Boomerang Fu - 4p. Fight each other by throwing boomerangs
• Kingdom Two Crowns - 2p. Side scroller town builder, protect your town against the evils outside
• Spelunky - 4p. Roguelike, delve into a cave searching for gold and riches

I actually have a Steam collection for this. It's mostly games I play when I have a handful of friends over. My favorites in the collection are:

• Boomerang Fu
• Duck Game
• Heave Ho
• Human Fall Flat
• Jackbox Mega Picker
• Keep Talking and and Nobody explodes
• Party Animals
• Pummel Party
• Overcooked 2
• Screen Cheat

Broforce is too much fun with friends.

Hammerwatch is a pretty fun top-down pixel dungeon crawler. There are other Hammerwatch games and it's also on consoles.

The "Lara Croft and the ________" games are a bit older but are fun puzzler dungeon co-op's. I really liked Temple of Osiris. I think these are also on consoles, but may be older consoles.

Stick Fight is a silly brawler. Also on consoles.

Party Golf is a fun and varied party game. Also on consoles.

It's older and I may be misremembering, but I think Hoard is co-op. It's on Steam still and you play as Dragons in a top-down gold hoarding thing. May be on consoles, but older ones. Pretty sure PS Plus Premium streaming has this under PS3 classics.

Hunted The Demons Forge is NOT local co-op on Steam but it is on PS3 and you can do it via PS Plus Premium streaming without a PS3.

On the rare moments that my friends come to my house we play some couch coop, most of the time is brawlhalla, but sometimes we play other games like hot shot racing, horizon chase, trick towers, etc.

Overcooked is an amazing couch coop

• Assault Android Cactus
  • Slick arcade-style twin-stick shooter with a pumpin’ soundtrack. Lots of characters with unique playstyles. Local co-op.
• Crypt of the NecroDancer
  • Bring rhythm to the classic roguelike. There's local and online co-op and lots of mods.
• Just Shapes and Beats
  • Rhythm bullet hell with a large EDM soundtrack. Local and online co-op.
• Keep Talking and Nobody Explodes
  • This is a stretch of the "couch" part of couch co-op. One player must defuse a bomb. The other players have a bomb defusal manual and must help the first player without being able to see the screen.
• Moving Out 2
  • Work together to drag and throw furniture into a truck. Chaotic co-op with physics, local and online.
• Gauntlet: Slayer Edition
  • 2014 revival of an 80s arcade classic. Co-op dungeon crawling action. Warrior needs food. Badly! Local and online co-op.
• Pizza Possum
  • Very soft stealth game about stealing and eating lots of food. Local co-op.

Yes definitely, here's my Steam 'Local Multiplayer' collection:

• Biped
• Move or Die
• Overcooked! 2
• Party Animals
• (Portal 2)
• Rayman Legends
• Screencheat
• Stick Fight: The Game
• Tetris Effect: Connected
• Ultimate Chicken Horse
• Unrailed!

Nintendo also has some great couch co-op games,for example:

• Mario Kart 8 Deluxe
• Super Smash Bros. Ultimate
• Nintendo Switch Sports
• Super Mario Party

I also very much agree with the other commenter here, it's such a shame that couch co-op is dying. The only ones still believing in it seem to be Nintendo.

Another game that's fun to play is Unravel 2, but for me the Steam version had all sorts of problems so I ultimately ended up refunding it again.

I find a lot of AAA games don't really do couch coop these days which is disappointing.

One game I always come back to (and it's ancient and Free to Play) is Awesomenauts. It's a cartoon sidescrolling hero shooter type thing, but it's a lot of fun.

I am currently playing "It takes two" together with my wife. It looks cute, has a story that is funny and really sad at the same time and the mechanics of the game change frequently. The occasional (optional) Minigames are really fun too!

I do play couch co-op, though some games are multiplayer some are single player and we hand it off or just experience it together.

Some of the games are: Mario party, Mario kart double dash (truly random items mod), Project Melee, Paper Mario thousand year door (amazing game), Kirby and the amazing mirror, and then a lot of one-offs mostly just trying out the random games.

A bit of an acquired taste, but the entire Earth Defence Force series can be played split screen (2P only). The best entry point into the series is EDF 5 (story reboot, QoL tweaks) which is often deeply discounted. Plus its direct sequel EDF 6 just released in the west last month

Duck Game, Trine, Little Big Planet are all fun.

Edit: Also, Hidden in Plain Sight is a Xbox 360 classic, it has a PC port now.

Diablo III was fun for my family, as was Minecraft Dungeons even though it's stagnant and abandoned now.

I didn't see Plateup! mentioned, similar to Overcooked but rogue lite with more emphasis on RNG and customization of the restaurant (through where you place the tables/utilities)

I don't know if "coop" is the right term, but Duck Game is awesome on the couch with two (or more!) people.

Nuclear throne

My sibling plays Ultimate Chicken Horse way too much for their health. I'm a fan of Duck Game, Castle Crashers, and Enter the Gungeon. I've also licked up Heave Ho and Pico Park, however those are more for party games for like 4 people or more.

Some I didn't see mentioned:

• Death Squared
• Rocket League
• various Switch games - Super Mario 3D World, Kirby (2P), etc

Nobody mentioned Guacamelee?

Overcooked (1 and 2) and Moving Out (also has 2 games). I have like all the "game show" games, too. Jeopardy, Wheel of Fortune, Family Feud, etc.

I also really like "Keep Talking And Nobody Explodes" but it's VR specific. Or at least, is way better with VR where the dude defusing the bomb can't see anything but the bomb and the room the bomb is in. I wish I had a physical manual for the other player, though...

Escape Academy is GREAT and ONLY GOOD with a partner. My partner and I played through most of it in a day and it’s been EXCELLENT so far. I’m not good at puzzles—they are. I still am having a blast.

Super Smash Bro's Ultimate is still the premier Couch ~~Co-Op~~ game for my circle of friends. We also play the JackBox party games and occasionally Mario Party.

I genuinely don't know what options are even available outside of Nintendo's fence anymore.

Edit: My reading comprehension is in the garbage today. Baldurs Gate 3 and It Takes Two.

Lara Croft and the Temple of Osiris was cute.

Resident Evil 5 & 6 also have co-op, and I believe revelations 2 as well

Untiled Goose Game (on the short side)

Cup Head

Extreme Exorcism

The last couch coop i did was with the dark picture anthology stuff from the until dawn devs where me and 3 other people would choose characters we would play as and pass the controller around and make decisions together. It was pretty fun.

A FANTASTIC underground couch co-op game is “Super Space _____” (read: Super Space Blank).

Imagine Asteroids, but everyone is controlling a cannon on the same ship, and the only means of propelling the ship is Newton’s third law. When your cannon hits an asteroid, it turns your color and when the asteroid leaves the game space the points for that asteroid go to the person whose color the asteroid is. If the ship leaves the game area, the game is over. It’s the best example of co-ompetitive I’ve ever seen.

It’s only available on Digipen’s website (link) since it was a student project but it’s magnificent for up to 4 players

Not a couch game, but I enjoyed Farenheit, Heavy Rain and Beyond Two Souls with my gf (we took turns).

As for couch games Kill Zone 3, Borderlands 1, 2 and TPS have been excellent!

I also made her play the Narnia game for PS2... Never again, I hope she agrees to play the Titan Titan game :(

EDIT: well, I somehow forgot about Mario Kart 8 and Super Smash Bros Ultimate... I was thinking of a more cooperative play style I think.

Torchlight

Torchlight 2

Plateup

Orcs must die

How to survive

A lot of what I wanted to post already got put here, but Bunhouse isn't here yet.

20xx, played it with a friend recently

Baldurs Gate 3 couch co op works incredibly well.

Yes, my wife and I play Diablo 4 together. During covid we played Mario Party on the switch with a couple of friends who we knew were also taking isolation seriously.

The new Pocky and Rocky game on switch is the last couch co-op game I played. Co-op is buried away slightly though - you either need to finish the game on single player or enter a cheat code to unlock it. I love all that old school stuff though!

The game itself is arcade perfection with beautiful pixel art.

XCOM 1 and 2 are significantly more fun when you have two players controlling the team

Overcooked, any version.

Fred & Bread looks amazing though I have not played it. Two penguins who are tied together with a rope have to climb a mountain together using nothing but each other and momentum

Borderlands 3! Admittedly its not the best of the series, but the couch co-op experience was great. I tried BL2 in couch co-op, but I found the compacted menus unbearable.