The King Cobra is one of the most challenging parts here. The body and hood are created using the Swept command with Scaling set to Perimeter Law and By Law Curve. The fangs used the same Swept command with Scaling set to Area Law Cubic with upper limit a constant and lower limit set to zero.
The head was a wireframe created with a combination of intersecting Sketches, Intersection Points, Curves on Surface Splines, 3D splines and 3D lines which was surfaced with Through Curve Mesh and Fill Surface and then Sewn together. Extend Sheet was used to fill in some of the gaps.
The eyes are Spheres placed with Points on Surface, the brows are Extrusions and the hood crest is an Extracted Geometry (Face) with Divide Face and a Thicken command. The tongue is similar. The lines on the neck are an Intersection Curve with a Sweep Along a Guide oval Subtracted from the surface and then patterned.