I worked on a very basic 3D logo (using Blender) for a project and I came up this:
Forgive me for asking, but why a 3D-Logo for a 2D-Library? I think it's odd.
Not to mention, SFML is not
strictly 2D. Many people use SFML as full-blown media library but for graphics, which they handle via OpenGL directly. So if one is making a 3D game in SFML and OpenGL, 3D SFML logo may come handy.