A couple of scripts that helps you optimize the non primitive 2D Colliders (Edge Collider 2D and Polygon Collider 2D).

You can change the level of optimization in the Editor with direct feedback in the Scene View to find a suitable compromise between performance and good approximation of the sprite shape. Usually you can loose quite a bit of points with virtually no change in the polygon contour.

The Edge Collider also creates a good edge collision shape instead of the default 2 point line.