Law's ability and it's not even close.
Mobility - Law teleports everywhere, even multiple times in mid-air. Shambles switches him with a substitute. Law could give himself a set of wings just to fly around like Monet. He could modify his legs like the centaurs of Punk Hazard and move around far faster than human legs allow. He could give himself a set of gills so he wouldn't drown like Jack but just remain paralyzed until someone rescues him. He can remove parts of his body and move them anyway.
Combat - Amputate, Radio Knife, Gamma Knife. That's just a sword cut and somehow there is three different effects. Injection Shot fires a stab attack like it was a gun. Counter Shock is an electrical attack as if physical damage wasn't enough. Sterben manipulates his sword and perhaps a deattached limb is necessary, but Law is attacking with a close range attack while his real body is hidden at medium or long range distances. Metz seems to be a one-shot cut attack if it hits your heart and he can perform it without a blade.
Terrain Manipulation - Amputate obviously severs objects and the environment in any way Law wishes and then he can manipulate it from there. He can piece objects or people back together in a way it doesn't make sense like the G-5 battleship and they will stay stuck anyway. Takt moves things like the sharp rocks that impaled and trapped Smoker's body. A storm of bullets was sent flying back to the marines. Law can control multiple objects at once and throw them at you from every direction.
Utility - Scan is like an x-ray than can find random things like Den Den Mushi for Law. Law can easily remove his own organs, float them in front of him, and then perform expert surgery on his own body. It might be pain free with his powers. Personality swap is incredibly useful for espionage, psy op, or simply cripping or boosting someone. Imagine Law swapping one his fodder crewmate's body with someone like Oven who can get run over by tanks, eat cannon fire to the face, take a Sanji kick that sends you into a house, eat lasers to the chest, and still get up from all that. That random fodder is now a powerful Heart Pirate and even might have access to Oven's DF ability.
I'm honestly astonished at how Law doesn't have a powerful crew full of chimera creations. Maybe Yonko Law will. Everything Moria, Big Mom and Kaido do to modify their crews, Law can do it 10 times better and there are no drawbacks I'm aware of, perhaps DF weaknesses. You want a guy with an elephant in his stomach? Why risk eating a faulty SMILE with only 10% chance of working, paying for a very complicated scientific process that can be sabotaged, only to gain DF weakness like drowning and seastone regardless if it works? Law sticks an amputated elephant head to your stomach and that's it
