Helper tool to identify missing component scripts on Prefabs in the project.

EditorUtils.cs

using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEditor;

public static class EditorUtils
{
    static void FindMissingScriptsInGO(GameObject go)
    {
        var components = go.GetComponents<Component>();

        foreach(var component in components)
        {
            if(component == null)
            {
                Debug.Log("Missing script found in: " + go.name);
            }
        }

        foreach(Transform child in go.transform)
        {
            FindMissingScriptsInGO(child.gameObject);
        }
    }

    [MenuItem("Tools/Find Missing Scripts")]
    static void FindMissingScripts() 
    {
        string[] prefabs = AssetDatabase.FindAssets("t:Prefab").ToArray();

        foreach(var prefab in prefabs)
        {
            string path = AssetDatabase.GUIDToAssetPath(prefab);
            
            GameObject obj = AssetDatabase.LoadAssetAtPath<GameObject>(path);

            FindMissingScriptsInGO(obj);
        }
    }
}