string path="Assets";//Assets/Scenes
if(Directory.Exists(path)){
    var dirctory=new DirectoryInfo(path);
    var files=dirctory.GetFiles("*",SearchOption.AllDirectories);
    for(int i=0;i<files.Length;i++){
        if(files[i].Name.EndsWith(".meta"))continue;
        if(files[i].Name.EndsWith(".unity")){
            Debug.Log("name:"+files[i].Name);
        }
    }
}