Most recently in my memory it's been minecraft. There was a wave of mods that were stealing things like discord access tokens, I don't have clear memory on all of the cases that I've been through, just that I always try and verify all mods I can now. I think I remember one for Lethal Company and looking online I'm seeing some referenced for Dota 2, Sims 4 and Slay the Spire.

Just learned Nexus mods is also pretty good about handling anything that's virus like, most of my modding experience has been external to that though.

Yep, this really bums me out. Wanted to try plenty of Minecraft mods but never wanted to go to the trouble to set up a secure environment, so I never did either.

As an only-tangentially-related aside, the difficulty of making mods for Windows games work on Proton also bums me out.

I wish some kind of cross-platform, sandboxed modding ecosystem existed solving enough problems that most modders would prefer to use it. I'm not sure that's even possible, though.