The Trapezoid tool is actually very similar to the Parallelogram tool. It allows you to create an isosceles trapezoid (a trapezoid where the non-parallel sides are equal) by defining one of the parallel sides and then either its next non-parallel side or its diagonal. You can use the Drag Constraints button to control the horizontal or vertical orientation of the sides or to define a vector to guide the drawing of the side. Here’s an example.

Also, as with the other polygon tools, the Bezier Points button lets you specify the number of bezier points on each side.