Love games co-op. I am much more likely to pay for a out the gage, full or near full price release if the game is co-op. And my co-op love and experiences are with people I know, so not not random groups pvping other random groups.
The Overcooked series is really, really high on the list. It’s just so easy to pick up and play with other people, even those who do not game… well. It’s just a blast.
Monster Hunter World is a distant second because it’s not very forgiving at all so those who are not good at games are going to bounce of it pretty hard.
Don’t Starve Together I kind of wish it had a little less inevitability to it, but it’s great fun, easy on the eye, hugely, hugely customizable and even those who are not good at games stand a fair chance when paired with those who are.
Vermintide/L4D - these games are coop FPS type games, and a weak player can still enjoy it with stronger players in the mix.
Gloomhaven/Divinity - These RPG or RPG type games are great but they both have huge weaknesses if you have someone who is just not a team player in the mix, like someone who wanders off and just won’t combing skills with others to get a good outcome.
CK3 - it’s a social game that you may or may not directly involve yourself with another player depending on where you are and what you do but it’s still fun to play alongside others.
So Overcooked is a champion right now because I’ve never had someone say yes and not enjoy it. And we can play for… hours, local OR online.