Creased is just a different way for the paper to be for a little while.

I am not aware of this setup, and so I'm musing and winging it, but I think what they're saying is that if you point at the paper and say "is this a sheet of paper" they'd say yes. And then you point to the crease and say "is this a crease" and they'd say yes, so it has identity, separate from the paper (as in creases and papers are not synonymous), but given that it's not counted when listing things in the room, it's also not a thing.

But I think for me it's not that tricky, because it's a feature of the paper. Like if there was a coat in the room with buttons, and you asked me what was in the room I wouldn't say a coat and three buttons, I'd say just a coat. And the coat has three buttons, but those are properties of the coat, not the room. And buttons are something that can stand-alone!

But if I had a sheet of paper with a button placed in the middle of it, but not attached, I wonder would most people say it was a sheet of paper and a button, or a sheet of paper with a button?

Nah, it's supposed to get you to think about what a thing is. You've listed random other examples of things but haven't really gotten closer to differentiating what makes a thing vs it not being a thing.

Thats what philosophy does. It's a crowbar we shove into the cracks in our models of how the world works to prove for weakness.

In the example above all you did was describe the paper better. It doesn't matter if it's blue or creased or whatever, the question is about the physicality (or lack thereof) of information. We're still not sure what happens to the information that passes through a black hole. Philosophy is a blind person's cane, helping to feel out unfamiliar territory.

That’s just infinite corners.

But can a particular element exist, without another element or elementary particle. Like I feel like you can't have hydrogen with out a proton and electron, and you can't have an electron without implying the existence on a proton

You're seeking the word "label," not "thing." At what point does it stop being a table, for example? When you take away 1 leg? 2, 3, all 4 (or more if it's a weird kind of table)? What if the removed legs are right next to it? What if the legs are on the other side of the world and new observers of the former table are unaware of this fact? Will they still call it a table or will the legs' absence alter their perception of the label? What if the legs are simply destroyed? What if an object was not originally built to be a table but someone said, "Hey, that's a table," and others around agree with them? Unga-bunga: the invention of language, the messy art of labeling. There is no real, objective table, just as there is no corner; we merely label it as such. Even for a long time I myself confused desks and tables until I realized that desks are basically tables meant to only be used from one side. They're all just made-up labels, every single noun out there.

And even with corners, at what point does it become no longer a corner? When 1cm is shaved off to round it? 2, 3? It therefore actually has substance because you can round it out, but all of these are ultimately labels/descriptors just driven by group consensus to make sense of the world.

The Greek Ship of Theseus comes to mind (fully renovate a dilapidated ship, piece by piece; in the end, is it still the same ship?). These are all human labels based on feelings. Nothing exists independently apart from conscious, sentient minds that apply, and remove, such labels.

Is a shelf a table?

It would only be parasitic if a round table was forced to be square against its desires. If a table wants to be square, the corners are being helpful.