Looking for some good 2 player games

Orcs must die 3, A Way Out, Horizon Chase Turbo, GRIP: Combat Racing, Garfield Kart - Furious Racing, Bud Spencer & Terence Hill - Slaps And Beans, ...

It Takes Two gained alot of Popularity.
Fighting games like Tekken, WWE and Street Fighter are obvious.

It Takes Two, Human: Fall Flat, Portal 2, Overcooked, Biped, We Were Here series, Heavenly Bodies, Trine series, KeyWe, Rocket League...

Hi, my son really likes to play with me a Worms game ( I have Revolution, but Armageddon is better), it is fun and there is a lot of laugh. We also played together Poly Bridge, it is not a 2 player, but we tried to suss it out together how to build a bridge, it was also fun and wacky in the later levels 😀.

Octodad is really funny. Hard recommendation from me.
Also I dont know how old your son is, but the lego (SW, Harry Potter, etc) games are great fun for young children. Played all of them with my brother when he was about 5-6, fun memories.

Some of my fondest gaming memories was playing Halo with my dad. You could try the master chief collection. Resident Evil 5 was also very fun to play through co-op, depending on how old is your son. And last but not least, Lego star wars: the complete or the skywalker saga if he's younger.

Had real fun with my niece playing Lara Croft: Temple of Light. Also, 'Ibb & Obb' but played this game a few years ago.

How old is your son?

Here's a few:

• Biped (3D puzzle platformer)
• HUNTDOWN (shoot'em up, very very polished, but hard)
• Horizon Chase Turbo (arcade racing game)
• Moving Out (my favourite overcooked-like party game)
• The Crackpet Show (roguelite shooter)
• BattleBlock Theater (2d puzzle platformer)
• Terror of Hemasaurus (very arcadey)
• Heavenly Bodies (platformer in zero g)
• Teenage Mutant Ninja Turtles: Shredder's Revenge (beat'em up)
• Greedland (blend between twin-stick shooter and vampire survivors)
• Rogue Heroes (really good adventure RPG)
• Barony (FPS roguelite)
• TwinCop (unique local co-op experience)
• Cat Quest 2 (great acessible ARPG)
• ADIOS Amigos (cute 2d platformer about space exploration)
• Door Kickers: Action Squad (tactical shoot'em up)
• Lovers in a Dangerous Spacetime (action game, nice co-op)
• Warhammer: Chaosbane (Midcore Diablo-like ARPG)
• Trine Franchise (Puzzle Platformer with combat)
• Neon Chrome (Twin-Stick shooter roguelite)
• Lost Castle (Hack'n Slash Roguelite, somewhat Beat'em Upy)
• Salt and Sanctuary (2D Souls-like)
• Super Blood Hockey (Arcadey retro Hockey game)
• Cave Blazers (2D Dungeon crawler roguelite)

I have a channel focused on PC co-operative games with lots of playlists - although the majority of videos are commented in PT-BR:
https://www.youtube.com/poepra2

Also have an uncommented gameplay playlist (the videos linked on the games are from this one):
https://www.youtube.com/playlist?list=PLXSJgzsctNy1e6OQPs3wbURjREvHzA_-g

So, feel free to ask for more!

Mount your friends
Genital jousting

Almost all of the above, + the We Were Here series (the first title is free-to-play, a spin off was free on launch). Asymmetrical co-op escape room. https://store.steampowered.com/bundle/12260/We_Were_Here_Series/

I loved playing through this (if your son is a teen or older): Operation: Tango https://store.steampowered.com/app/1335790/Operation_Tango/
The huge +1 for this one is that while it's paid, there's a free friends pass so your son or anyone else can play with you for free, only need one purchase of the game.

Also hasn't been listed yet: Unrailed! https://store.steampowered.com/app/1016920/Unrailed/
Same vibes as Overcooked!/Moving Out and whatnot, this one's about building a railroad while the train is moving. There's a free demo, and it has been free on Epic at some point (if you don't mind playing there).

Last one, since Overcooked! has been mentioned, it has a sequel (Overcooked! 2) and some kind of remaster/repack/definitive edition (Overcooked! All You Can Eat); and also the competitor Plate Up! that has a bit more detailed gameplay and a free demo. https://store.steampowered.com/app/1599600/PlateUp/
Both Overcooked! games have been free on Epic before (can serve as a demo if you prefer playing on Steam).

Stick Fight: The Game
River City Girls
Move or Die

off the top of my head
audio surf
crawl
Katamari Damacy
goat simulator
Guacameele
a hate in time
almost any lego game
lovers in a dangerous space time
make way
monoco
octodad
rock of ages 3
speedrunners
any trine game
x morph defense

The Deadly Tower of Monsters is one I don't see mentioned often in these co-op threads and it's a great joy to play in co-op. Also it's a hoot.
The game itself is an homage to B movies of the 50ies and there's a running commentary by the "director" that's just hilarious.
Can't tell you how many times I got killed dead because I was laughing my ass off at the commentary.

Magicka 1 and 2

Shift Happens 👍

Some games i really enjoy in coop (sorry no time to put links)

A way out
Bang-On Balls: Chronicles
It Takes Two
Orcs Must Die! 2
Orcs Must Die! 3
Raft
Tick Tock: A Tale for Two
Trine 4
We Were Here (4 games)