* Volcanoes: The subducting plate melts, creating magma that rises to the surface and forms volcanoes. This is why many volcanic mountain ranges occur along the edges of continents.
* Trench: The bending of the oceanic plate creates a deep depression in the ocean floor called a trench.
* Earthquakes: The friction between the plates generates seismic waves, causing earthquakes.
* Island arcs: If the subduction occurs along a chain of volcanoes, it can create a chain of islands called an island arc.
So the answer to your question is volcanoes, trenches, earthquakes, and island arcs.
