Unsolicited audio and pvr addons

[supernano]

I have several addons installed in my system which I didn't install and many of which are disabled. I have tried uninstalling them, but after reboot they come up again. They are in the categories: audio decoders, audio encoders, audio dsp and pvr clients.
I'm trying to figure out how they got there. Are they installed by default in kodi for some reason? They particularly bother me, although if they're not needed I'd rather not have them there taking up space.