Unity Hierarchy Cleaning/Grouping Tool

For our class Rapid Prototyping we got the assignment to make a tool for unity, based on what we would like from our previous experiences working with others. I personally noticed that in larger projects I worked on the hierarchy becomes quite a mess after a while and so I decided to make a tool to help with that.

Because this was for Rapid Prototyping we could only work on it for 90 minutes a week and we only have about 4 weeks in total to finish our tool. We had to make this tool during the second period of our second year, this was around January/February.

[MenuItem("Window/Hierarchy Cleaner")]
    static void Init()
    {
        CleanerWindow window = (CleanerWindow)EditorWindow.GetWindow(typeof(CleanerWindow));
        window.Show();
    }

    private void OnGUI()
    {
        _UseExistingParent = EditorGUILayout.Toggle("Use existing Parent?", _UseExistingParent);
        _TagName = EditorGUILayout.TagField("Tag to clean: ", _TagName);

        if (_UseExistingParent == false)
        {
            _ParentName = EditorGUILayout.TextField("Name of new Parent Object", _ParentName);

            if (GUILayout.Button("Spawn Parent"))
            {
                GameObject obj = new GameObject();
                obj.name = _ParentName;
            }
        }

        if (_UseExistingParent == true)
        {
            _ParentObject = (GameObject)EditorGUILayout.ObjectField("Parent Object", _ParentObject, typeof(GameObject), true);
            if(_ParentObject != null)
            {
                _ParentName = _ParentObject.name;
            }          
        }
        
        if (GUILayout.Button("Clean!"))
        {
            List<GameObject> gameObjects = new List<GameObject>();
            GameObject go = GameObject.Find(_ParentName);
            foreach (GameObject obj in GameObject.FindGameObjectsWithTag(_TagName))
            {
                gameObjects.Add(obj);
            }

            for(int i = 0; i < gameObjects.Count; i++)
            {
                gameObjects[i].transform.parent = go.transform;
            }
        }
    }
[MenuItem("Cleaner/Create New Object For Parenting %_#_g")]
    private static void ParentToNewObject()
    {
        List<GameObject> objects = new List<GameObject>();

        for(int i = 0; i < Selection.gameObjects.Length; i++)
        {
            objects.Add(Selection.gameObjects[i]);
        }

        GameObject go = new GameObject();

        for(int i = 0; i < objects.Count; i++)
        {
            objects[i].transform.parent = go.transform;
        }

        go.name = objects[0].name + "s";
    }

    [MenuItem("Cleaner/Use Existing Object For Parenting #_g")]
    private static void ParentToExistingObject()
    {
        List<GameObject> objects = new List<GameObject>();

        for (int i = 0; i < Selection.gameObjects.Length; i++)
        {
            objects.Add(Selection.gameObjects[i]);
        }

        GameObject go = objects[0];

        for(int i = 1; i < objects.Count; i++)
        {
            objects[i].transform.parent = go.transform;
        }
    }