Grip work is a whole world unto itself... for example the Captains of Crush grippers I mentioned earlier. Their #4 gripper which takes 365 pounds of pressure to close has only been close by 5 (I think) people on the planet despite it existing for over 25 years. The dedication to closing that gripper is insane... and even if you have the drive chances are you will never do it.
Some of the few that have had built custom rigs and equipment just to aid in the training for this feat.
Then there is breaking box wrenches with the bare hands.... rolling frying pans... nail bending... so many things.
Another example would be card tearing... I was pretty happy with myself when I ripped my first deck last year... took me almost a minute.
Then you have freaks like John Brookfield that can tear ONE HUNDRED decks in just double that time.
I'm in no way and elite grip person but I have done many different things with it. Just one of those odd things I like to do... wish I devoted even more time to it.