I know that a non-developable surface (like sphere, ellipsoid, paraboloid, hyperboloid,hyperbolic paraboloid helicoid, catenoid etc.) can't be flattened onto a plane without distortion (like stretching & contraction) & it has zero Gaussian curvature. Thus it is not possible to truly make a non-developable surface developable.
Therefore a non-developable surface can be approximated by a surface consisting of flat faces as plane polygons like triangles, quadrilaterals or other polygons of as minimum size as possible for best approximation such that there must be no change in the shapes & dimensions of the flat faces when transformed to the desired surface. This makes a non-developable surface as a polyhedron & a polyhedron is developable surface i.e. it can be easily flatted onto a plane without distorting any of its flat faces just by unfolding flat faces at their mating edges. Thus, a non-developable surface can be made develpable.
One of the best methods of doing so is dividing a curved surface into tiny plane-triangles called Surface Triangulation as shown in figure below

My question: Is there any other method to make a non-developable surface developable besides using net of triangles, quadrilaterals or n-polygons?
Any help will be greatly appreciated.

Other developable surfaces are cylinders, cones and other less known. See https://en.wikipedia.org/wiki/Developable_surface.
You can approximate your non-developable surface with patches of those.