What types of geologic structures would you expect to find in an area that had undergone compressional tectonic stress?

Folds.

Explanation:

A fold occurs when an originally flat or a plane surface of sedimentary rocks undergoes a bent or a curve and that may lead to permanent deformation. And are formed due to the slumping of the sedimentary materials. They can form under the conditions of the compressional stress, hydrostatic pressure, and temperature gradient. A set of folds is distributed at a region scale makes the fold belt and is commonly found in the orogenic zones or the mountain building areas. These folds are of various types as Anticlines, Synclines, and Antiforms.