Unity:親を含めた子オブジェクトの全てのマテリアルの取得

GetMaterials

private List<Material> materials = new List<Material>();

foreach(Transform child in transform)
{
    if(child != null && child.renderer != null && child.renderer.material != null)
        foreach(Material mat in child.renderer.materials)
            materials.Add(mat);
}