An origami extrusion is a folding of a 3D object in the middle of a flat piece of paper, using mechanisms called 3D gadgets. As examples of 3D gadgets, the conventional pyramid-supported ones generalizing the cube gadget are known, which create a top and two adjacent side faces of a frustum using two pleats. In this paper we present new flat-back 3D gadgets which improve the conventional ones in several respects. In particular, for any conventional gadget there are an infinite number of our gadgets downward compatible with it. Also, we can change the directions of the pleats in a wide range.