ClearMissingReferenceExample

using System.Collections;
using System.Collections.Generic;

using UnityEngine;

public class ClearMissingReferenceExample : MonoBehaviour
{
    public List<GameObject> gameObjects;

    [ContextMenu ("Create GOs")]
    void CreateGOs ()
    {
        for (int i = 0; i < 5; i++)
        {
            GameObject go = new GameObject ();
            go.name = "GameObject" + go.GetInstanceID ();
            go.transform.SetParent (transform);
            gameObjects.Add (go);
        }
    }

    [ContextMenu ("Clear MissingReference")]
    void ClearMissingReference ()
    {
        gameObjects.RemoveAll (item => item == null);
    }
}