Picking from the list, probably shape shifting for the novelty of it.
Not constrained to the list, 'electric powers'. I've spent more time than a person should realistically be spending looking at the fictional possibilities of electric based super powers
(because I have way too much free time). Most *things* don't tend to do it much justice and pretty much just stop at "they zap you" when it could be so much cooler. It's still not the greatest power, just seems fun to me.
You can do all those powers with shapeshifting
But you would have to take on a new form to do so which
could be more trouble than it's worth.
It also depends on whether you're restricted to real life things or not. If you're not restricted and you take on another super heroes form, do you get their powers from turning into *thing* or just their appearance? For somebody like the Flash where he looks otherwise human and you don't know how exactly their powers work, would you still get their powers even though your body wouldn't know how to recreate what it is exactly that makes him really fast? Would you be able to turn into Batman and take off your mask to find out Batman is Bruce Wayne if you didn't already know that Batman is Bruce Wayne?
That's something I've always wondered, since I brought it up...Do shapeshifting people in fiction, like, know biologically how the things they turn into are actually able to fly etc? I always thought you would need to know yourself how a duck is scientifically able to fly if you're going to turn into one to fly (or swim in pools of money. Yano, duck stuff). It's always why I assumed Mystique can't use other mutants powers when she turns into them.
And are you restricted in the sizes of what you can turn into, like the T-1000 and how it can't change into objects significantly larger or smaller in size than itself. Can you turn into objects, and can they be objects with more complex structures with moving parts such as a bomb or projectile weapon?
...I've probably over thought this.