A cluttered place is not always the same as a messy place. A cluttered place has too many things in it, but those things might be neat and clean and organized. Here's a makeup desk that's clean and organized, but it's cluttered: there's just so much stuff in such a small space.
And that brings us to an important point: whether or not something is "clutter" depends on the person. In my opinion, that makeup desk is cluttered, but whoever owns it might have a very different opinion! I say that all those products are clutter, but you could say that they're all important and that you need all of them. Calling stuff clutter is almost as insulting as calling it junk or trash, so be careful if you call someone else's stuff clutter.
Clutter is often stuff that you can see and touch, but it doesn't have to be. Your day could be cluttered with too many activities. Your mind could be cluttered with too many worries. And a song could be cluttered with too many instruments, or too many vocal parts.