A quick review of photographs of galaxies will reveal that not all galaxies are orientated in the same plane as the field of view from Earth. Some galaxies are parallel to our field of view and we see them side on. Others are perpendicular to our field of view and we see them as if we are looking either from above or below them.
Given this fact, it would be fair to assume that the orientation of planetary systems is similarly varied. Not all of them are parallel to our field of view.
All the exo-planetary systems I am aware of have been seen in a side view perspective and any exoplanets have been detected by either a wobble of the star at the center of the planetary system or via dimming of the star's light as the exoplanet transits the star.
Have any exo-planetary systems been discovered that are perpendicular to our field view, looking from above or below the system and if so, how have any exoplanets in these systems been detected? If no such systems have been observed, how would astronomers detect exoplanets in such systems?