Haven't used one, but when I was researching how to remove the agitator on my Maytag 606, I ran across this kind of product. I *think* it's an inflatable device that you slide around the bottom of the agitator, and then inflate it to lift the agitator from the bottom.
If so, I do not think it would work with blue Maytag agitators, as the bottom of these is flexible and might not take the force. (I was told here the best thing to do would be to fill the tub with very hot water to soften the o-ring that holds the agitator in place, but never got around to that).