What are some good cooperative shooters? Hidden gems?

Wondering what the people on Lemmy think :)

Looking for stuff to play mostly with 2 players, but anything is fine.

I looked through https://store.steampowered.com/category/action_fps/?facets13268=6%3A1&flavor=contenthub_toprated (Shooters with tag "coop") but for some reason there's stuff like Counter-Strike and Team Fortress etc. in there, and while you can play those cooperatively, really they're competitive games.