I'm currently playing V Rising right now with my wife after Divinity 2. We are LOVING it. Definitely give it a try!

I enjoyed playing Toodee and Topdee with my roommate. Fun puzzle game. Can be played singleplayer or multiplayer. https://store.steampowered.com/app/1303950/Toodee_and_Topdee/

Minecraft Dungeons is also quite fun for co-op. https://store.steampowered.com/app/1672970/Minecraft_Dungeons/

Survival Coop

• ASTRONEER
• Don't Starve Together
• Grounded

Actiony

• BIGFOOT
• Children of Morta
• Content Warning
• Broforce
• Gauntlet
• Generation Zero
• Road Redemption
• Warhammer: Vermintide 2
• Worms Armageddon
• Shadow Warrior 2

Sportish

• Blood Bowl 2

RPGish

• Divinity: Original Sin 2
• For The King
• For The King 2

Strategy

• ENDLESS Legend

Puzzle

• We Were Here
• We Were Here Together
• We Were Here Too

Cozy

• Viscera Cleanup Detail

I haven't seen Rayman Legends mentioned, so I'll throw it out there. It's a pretty flawless game for what it tries to be, and it's a lot of fun to play with a friend. The musical levels are just extraordinarily crafted. Definitely recommended if you're into platforming at all (and even if you're not it's worth a shot!)

for local coop of course portal and as a bonus, kid safe, - it takes two, biped.

Cult of the Lamb's latest content release is bringing 2-player local coop

Wildermyth is an awesome indie RPG that I've had a lot of fun with as a two-player coop game. It's a turn-based dungeon crawler with a strong focus on role play and party dynamics.

I hear great praise for Across the Obelisk as a coop game from my friends, although I personally bounced off of it. It's a roguelite deck builder like Slay the Spire, but with multi-player, lots of meta progression, and a heftier time commitment for each run.

Gunfire Reborn is a roguelite looter shooter that's a blast in coop. I think it's still in Early Access, but what's already there is enough for me to be happy with it as a full game. To me it's a spiritual successor to Borderlands in combat and gamefeel, but without the grinding.

Remnant 2 and Deep Rock Galactic are the best that come to mind rn.

Remnant 2 is dark souls with guns and coop actually changes the game in some ways to better enable teamwork to make the dream work.

Deep Rock Galactic is just a wonderful little title about space dwarves mining a crazy bug planet. 100% randomly generated. Each of 4 classes feel like they bring something unique to each mission.

Stardew Valley. My wife and I have sunk well over 1000 hours into it and we still aren't bored. The amount of mods for it is insane and gives so much more depth to the game, but vanilla is super well done as well.

Earth Defense Force. You can probably get 4.1 on a sale really cheap and that could be a decent introduction to the series as a whole, it also has the best overall story tone in my opinion, made of 110% grade B cheese

If you two enjoy it and don't feel burnt out, you can later get EDF 5, which has several QoL updates compared to 4.1, but tends to have a higher price.

Warframe

Subnautica can be played together using the Nitrox mod

https://nitrox.rux.gg/

If you don't mind an MMO subscription fee, you might try A Tale In the Desert:

https://www.desert-nomad.com/

It's fairly niche, and it's been years since I've played it, but it seems to still keep an active player base. It's much more cooperative than most MMOs, with very little PvP. It's like the whole community is working together to build a civilization.

Unravel 2

Pikmin 3

Overcooked

Elden Ring with the Seamless Coop mod looks like great fun if you enjoy that type of game. I've wanted to try it for a long time.

Popping in to suggest Ship of Fools and Cult of the Lamb

Ship of Fools was shorter than I'd like but lots of fun. Currently playing through Cult of the Lamb co-op and and we've been having a blast

My wife and I just finished Super Mario Wonder. It was a lot of fun. Every level has a weird psychedelic section that completely changes the players or the level temporarily. It shakes it up and gives a lot more variety than the other side scrolling Mario games.

You can play Stardew Valley in multiplayer co-op mode, it's also quite cheap at $14, it's available on every platform and even has excellent Linux support

Super Mario 3 is pretty sweet

Serious Sam - almost any version!

Ark survival evolved is something my husband and I enjoy playing together that's quite fun. The base building and dino taming together is very enjoyable if you're on a private server.

If you give this one a try, make sure whoever is hosting sets their server to private and invites the other person via steam. Otherwise you might get randos.

Project Zomboid. Feels like a Sims game with zombie and great survival elements. Arguably, the best zombie survival game to hit the market. Supports split screen couch co-op.