There are 252 different orthographic projections. They form 63 groups of four, that look similar. They are all shown below. Within such a group, each image has a reflection at the antidiagonal and an image with the same outline.
Some images also have horizontally or vertically mirrored equivalents. And a few have all eight rotations and reflections in the symmetry group of the square. (These are all in the third section. The former in 24 rectangles and 48 long parallelograms, the latter in 48 hexagons.)