Plungers have either a 2" end, or the black rubber plungers have a 2" pullout on the end.
Either way, with any brand of toilet, you would leave a little water in the bowl, and use the small end of the plunger in the bowl.
Using small strokes up and down, basically vibrating the water, then slightly pulling up a bit.
Normally the water will suck down at that point.
Another method would be using a five gallon bucket and pouring directly into the bowl.
Or using a closet auger to push out whatever is lodged in the trapway.