I do love how many more casual co-op games we're seeing lately, and it looks like S.K.R.U.B. Squad may be one to add to your list.
https://www.gamingonlinux.com/2025/11/the-multiverse-is-a-mess-so-you-and-friends-will-get-cleaning-in-s-k-r-u-b-squad/

#Steam #IndieGame #Upcoming #Casual #Proton #OnlineCoop

Taking inspiration from incremental games with a long progress tree to unlock, NodalBastion is a tower defense game that just keeps on going.
https://www.gamingonlinux.com/2025/11/nodalbastion-is-a-delightful-mixture-of-tower-defense-and-incremental-progression/

#Steam #IndieGame #Upcoming #TowerDefense #Demo #NativeLinux

This is the kind of chaos I love to see, and very fitting from Vampire Survivor developer poncle, with the casual deck-builder Vampire Crawlers.
https://www.gamingonlinux.com/2025/11/vampire-survivors-gets-turned-officially-into-a-crazy-deck-builder-with-vampire-crawlers-from-poncle/

#Steam #IndieGame #Upcoming #Deckbuilder

Coming across it by pure chance recently, Bioflux - Horde is an upcoming survival game with enemy numbers that actually look like true hordes of infected.
https://www.gamingonlinux.com/2025/11/bioflux-horde-is-a-survival-game-where-the-infected-numbers-look-insane/

#Steam #IndieGame #Upcoming #Action #Survival #OpenWorld #Proton