lens
pencil
lawn chairs
hands on a clock
arrowhead...
Some examples are: circle, square, rectangle, right angle triangle, equilateral triangle
leaf
Some examples are a square, rectangle, that is all I know so far
There's no such thing as the diagonal of an angle anyway. If there's an irregular polygon that has some reflex angles in it, there's no reason the polygon can't have diagonals that terminate in them.
buildings, desk, door
Some two-dimensional shapes: square triangle rectangle diamond circle trapezoid
Some examples of 3D shapes with angles include cubes, pyramids, and rectangular prisms.
A kite, if the topmost angle is right and none of the others are.
Cube, pyramid, cone, cylinder.
A ramp, angle of mountain
Some examples of squares are chessboard, carom board, square rubber stamps, and tiles on the floor.
A sphere, an ellipsoid, a toroid are some examples.