概要

using System.Linq;
using UnityEditor;
using UnityEngine;

public class Example
{
    [MenuItem( "Tools/Hoge" )]
    private static void Hoge()
    {
        var hasMissing = PlayerSettings
                .GetPreloadedAssets()
                .Any( x => x == null )
            ;

        Debug.Log( hasMissing );
    }
}