概要

using System.Linq;
using UnityEditor;
using UnityEngine;

public class Example
{
    [MenuItem( "Tools/Hoge" )]
    private static void Hoge()
    {
        var paths = Selection
            .GetFiltered<DefaultAsset>( SelectionMode.DeepAssets )
            .Select( x => AssetDatabase.GetAssetPath( x ) )
            .Where( x => AssetDatabase.IsValidFolder( x ) )
            .ToArray();

        foreach ( var path in paths )
        {
            Debug.Log( path );
        }
    }
}