An example how to iterate over all Unity GameObjects in a hierarchy.

GameObjectsIterator.cs

using UnityEngine;

///
/// an example how to iterate over all GameObjects in a hierarchy
///
class GameObjectsIterator
{
    ///
    /// an example how to print root GameObject and all it's
    /// children to debug console
    ///
    public static void PrintAllObjects(GameObject root)
    {
        foreach (var go in AllObjects(root))
        {
            Debug.LogFormat("GameObject {0}", go);
        }
    }

    ///
    /// makes an enumarable that contains all game objects starting with root
    ///
    static IEnumerable<GameObject>AllObjects(GameObject root)
    {
        yield return root;

        foreach (Transform ch in root.transform)
        {
            foreach (var go in AllObjects(ch.gameObject))
            {
                yield return go;
            }
        }
    }
}