The periodic table is open at the bottom.

We have found the first 118 ones and filled up the top 7 row in the periodic table.

People are actively working on getting started on the 8th row and beyond. The problem is that all these elements are unstable. And the last few ones that we "discovered" were already so unstable that they only existed for a tiny moment before decaying.

It gets harder and harder to make them as we go along and what you get out of exists for shorter and shorter amounts of time.

There is expected to be a region deeper down in the periodic table where elements become more stable again. But that is only relative to all the other stuff around it.

Don't expect anyone to come up with a magic metal tomorrow but don't be surprised if at some point in the near future you read an article about a new element created in a lab.

There is also the possibility of making stuff out of things other than combinations of protons, neutrons and electrons as our elements are.

Don't expect anything there that will freely exist in nature and that you can touch with your won hands, but the possibility for stuff to exist however briefly outside the normal domain of chemistry is there.

Most sci-fi stories either invoke magic or wave their hands or don't discuss at all how their wonder materials allows for timetravel, ftl, anti-gravity or ist just incredibly hard and unbreakable.

That is not something we should expect from any new elements or undiscovered particles or matter.