Find all missing scripts in unity3d scene

SelectGameObjectsWithMissingScripts.cs

using UnityEngine;
using UnityEditor;
using System.Collections.Generic;
using UnityEngine.SceneManagement; //3
 
public class SelectGameObjectsWithMissingScripts : Editor
{
    [MenuItem("Tools/WPAG Utilities/Select GameObjects With Missing Scripts")]
    static void SelectGameObjects()
    {
        //Get the current scene and all top-level GameObjects in the scene hierarchy
        Scene currentScene = SceneManager.GetActiveScene();
        GameObject[] rootObjects = currentScene.GetRootGameObjects();
 
        List<Object> objectsWithDeadLinks = new List<Object>();
        foreach (GameObject g in rootObjects)
        {
            //Get all components on the GameObject, then loop through them 
            Component[] components = g.GetComponents<Component>();
            for (int i = 0; i < components.Length; i++)
            {
				Component currentComponent = components[i];
 
                //If the component is null, that means it's a missing script!
                if (currentComponent == null)
                {
                    //Add the sinner to our naughty-list
                    objectsWithDeadLinks.Add(g);
                    Selection.activeGameObject = g;
                    Debug.Log(g + " has a missing script!");
                    break;
                }
            }
        }
        if (objectsWithDeadLinks.Count > 0)
        {
            //Set the selection in the editor
            Selection.objects = objectsWithDeadLinks.ToArray();
        }
        else
        {
            Debug.Log("No GameObjects in '" + currentScene.name + "' have missing scripts! Yay!");
        }
    }
}

Absolute garbage

Try actually running your scripts before posting them, it won't even compile.
Your script works with the following changes:

#if UNITY_EDITOR
using UnityEngine;
using UnityEditor;
using System.Collections.Generic;

public class SelectGameObjectsWithMissingScripts : Editor
{
    [MenuItem("Tools/Utilities/Select GameObjects With Missing Scripts")]
    static void SelectGameObjects()
    {
        List<GameObject> allObjects = new List<GameObject>();
        foreach (GameObject obj in FindObjectsByType<GameObject>(FindObjectsSortMode.None))
        {
            allObjects.Add(obj);
        }

        List<Object> objectsWithDeadLinks = new List<Object>();
        foreach (GameObject g in allObjects)
        {
            Component[] components = g.GetComponents<Component>();
            for (int i = 0; i < components.Length; i++)
            {
                Component currentComponent = components[i];
                if (currentComponent == null)
                {
                    objectsWithDeadLinks.Add(g);
                    Debug.Log(g + " - Found object with missing scripts", g);
                }
            }
        }
        if (objectsWithDeadLinks.Count <= 0)
        {
            Debug.Log("Not Found");
        }
    }

}
#endif