Common Elemental Termolecular Reactions
Termolecular reactions almost never happen.  The chance of three molecules "colliding" at the same instant is so small as to be ignorable.  

On the other hand there are "almost" termolecular reactions when one molecule hits another and "sticks" to it, and then a third molecule hits the two that are stuck together.  This most often happens when one of the molecules is part of a solid.  But this is really two sequential bimolecular reactions.