I don't think I've had any particularly bad ones. In fact I don't remember having any since my age was in the single digits tbh. The only time I remember having malware was once when I tried to install iTunes on Windows for some reason, and I got infected with some kind of malware from trying to download this. I don't remember what exactly it did—I think it was just adware that interacted with your browser, nothing too crazy. I think I may have done a fresh install or factory reset to get rid of it. I was really young at the time and I don't recall getting malware since. I've definitely never (consciously) experienced malware on Linux, yet. (I say consciously cause for all I know maybe someone's bugged me with a keylogger I've not detected idk. Hope not!)