If you’re looking for something geared more introductory to co-op board games, Castle Panic is good:

https://boardgamegeek.com/boardgame/337394/castle-panic-deluxe-collection

Horrified is a great co op board game. Can mix it up a few times.

Replayability will be limited, but I’ve only played it around 4 times since owning it October 22.

Lots of great games mentioned. If you have younger ones that you want to bring in to the fold, there’s a couple good ones I’ve had success with:

• Sky Magic: you play as fantastical creatures trying to brave an oncoming storm, everyone needs to get to safety to win, so some strategizing together to optimize each other’s paths is rewarded.
• My first Castile panic: simplified version of the classic suitable for the younglings.

I prefer co-op games over others, so I love this question.

• Castle Panic
• Pandemic (with the easy difficulty level for beginners)
• Eila and Something Shiny

Coop games are tricky because many allow “quarterbacking”, which, while really being a player problem, I blame on bad game design. (For example Pandemic could really be played solo with 4 stations)

So you need coop with asymmetrical information and nobody can have all the information.

Hanabi is a great classic example of a game where nobody can see their own cards, but there is a limit to the amount of info you can give out.

Just One is a newer example of a coop party game.