Would be great if you updated this post with new games you enjoyed 😊

One of my favorite games to play with my SO is Out of Space the vibe is very similar to Overcooked but it's procedurally generated and a lot more chilled out, i.e. less chaos.

If you enjoy escape rooms try out Escape Academy, haven't seen anyone mention it but it's really a blast!

https://store.steampowered.com/app/1812090/Escape_Academy/

Unravel 2 :) It's a beautiful little co-op game with lots of puzzle-y problems to solve and some dynamic ones as well

The cult of the lamb

Lovers in a Dangerous Space Time

Manage your malfunctioning space ship together while fending off waves of enemies.

Very fun.

Degrees of Seperation - 2D puzzler with wonderful scenes and visuals

Heavenly Bodies - 2D puzzler about astronauts and 0 gravity environments

Unrailed - isometric 3D. A train starts driving and you need to gather resources and build tracks etc.

Wobbly Life - 3D fun game, no real objective, just many quests and activities throughout the world

My gf is pretty new to video games but these are a few she enjoyed

Trine 2/3

Snippets

Castle crashers

Unravelled

Diablo 3

Children of morta - my gf also doesn’t really like pixel art but this turned out to be one of her favourite games

We just started the spiritfarer. Absolutely worth it

Spelunky 1 & 2

Monster Prom, Monster Camp, Monster Roadtrip

Also seconding Kingdom: Two Crowns

A few options me and my partner have enjoyed:

Bunhouse - a non-management-heavy farming simulator but you are bunnies growing plants. Cute as hell. There is a sequel where you run a bakery too but we haven't got round to that just yet.

Unrailed - might fall into the overcooked catagory, but when it gets hard and goes wrong it tends to be a looming inevitablity, not a frantic panic

Nidhogg - a 1v1 fighter, but is quick fire frantic sword fights you can button bash through which is wildly entertaining in 5 min bursts.

I'm not even a huge platformer guy, but Rayman Legends is absolute peak and a fantastic, chill co-op game. The music levels in particular - where the already great soundtrack is synced in time to your jumps and hits - are incredibly satisfying and so well made.

I'd also be remiss if I didn't suggest Blue Prince. It's not co-op per se as it'd only be one person at a time "driving", but the game is about puzzle solving so who holds the controller doesn't really matter. It's a fantastic game if you enjoy puzzles and escape rooms. My sister isn't even a gamer at all but I recommended it to her fiancé and they've been playing together and even she's been enjoying it a lot. From my own experience playing it on my own I also think it would be much more fun if playing alongside someone else. I've often missed having someone to bounce ideas off when stuck.

Broaden your horizons, start using emulators.

Star Wars: Jedi Power Battles

Kirby and the Forgotten Land

Super Mario Wonder

Any of the Warriors games (just don't buy it, don't reward them for releasing the same damn game 20+ times)

Legend of Mana (highly recommended, please don't sleep on this)

Destroy All Humans 2

Ratchet: Deadlocked

Divinity: Original Sin

Resident Evil 6

Halo: Master Chief Collection

Lego Star Wars

The Tales games are long and go up to 4 players. I'd recommend them if you have more people to join.

Be prepared for a few roadbumps while you acclimate yourself to using emulators. It won't be smooth at first, but it gets easier the more familiar you become with it.

Death Squared. Puzzle solving, each player controls two blocks on the map used to solve the puzzle.

Keep talking and nobody explodes could be a fun one, only needs 1 device and the other player needs the manual which can be on a phone or printed out. You could even play it over a phone call.