Sensations are similar to emotions, except they are more simple and can be building blocks for emotions. You can experience them inside the body, or outside. They can be caused from physical or nonphysical stimulus.
I assume that the nervous system is what allows us to feel them, sometimes the organs might be a chemical stimulator and then the brain is the master center for processing the stimulation.
Something like hunger or repulsion wont be added for example. But what is the underlying sensation of hunger? An internal contraction, so contraction would be our sensation.
Pain - Uncomfortable, nervous system sensation, usually extremely hot or cold, prickly or electric.
Pleasure - A nice sensation, from enjoyable food, relaxation, good touch or sexual pleasure.
Pressure - Weight or a force against you. Can be from a central area like organ expansion.
Hot - A drying, mildly discomforting sensation if too strong. Radiates energy.
Cold - Contracting and sharp, uncomfortable and tingly.
Wet - Soft and moist feeling, can be cold or cooling.
Sharp - Pointed, small and uncomfortable. Something pushing.
Dry - Tight, tense leathery and rough.
Granular - Sandy, small fine particles. Tingly and stimulating, dry.
Smooth - Curved, relaxed, skin like and plastic like.
Magnetic - A wide force, cold and heavy.
Electrostatic - Tense, hot, fine like thread and prickly.
Air - A soft and subtle pressure. Can be cooling or warming and even moistening.
Contraction - A tension feeling, opposite of expansive pressure.