Any sturdy flat item that can support your body weight and will not move can be used as a substitute item to perform this movement with.
Muscles of your butt.
Muscles spanning the front of your thigh.
Muscles spanning the back of your thigh.
Center region of your back, spanning from the pelvis to just below the neck. However, parts of it are hidden beneath other muscles. The lower portion is the most visible.
Bodyweight
This means that the exercise requires you to use your bodyweight as resistance but you also need other equipment to successfully perform the exercise.
Large Textbook
Anything that is 3-4 inches high and can handle you standing on it is fine.
Exercises that target the same primary muscle groups and require the same equipment.
Exercises that target the same primary muscle groups with different equipment
