The number of places that were never colonized by Europeans is quite small. China, Japan (though occupied by the USA after WWII), Korea (Though colonized by Japan), Turkey, Mongolia, Tibet (though colonized by China), Thailand, Afghanistan, are the countries which spring to mind.

Some of those countries could be said to be the only successful resistors to European colonization. In other places there were temporary "triumphs" which did not succeed in resisting European colonization.