Hammer Grip
Just make a fist. Good for power, not so much for control.
Reverse Hammer Grip
Good for when you need to keep the knife steady and are moving whatever you’re cutting, rather than the knife itself.
Sabre Grip
Like the hammer grip, but you put your thumb on the spine for more control.
Thumb Push
You can use your thumb to push the blade for precise cuts.
Chest Push
You can use your chest as a point of contact, too.