Simple helper Editor method to list out all known asset bundles and their bundle-names.

ListBundles.cs

using UnityEngine;
using UnityEditor;
using System.Collections;

public class ListBundles : MonoBehaviour
{
    [MenuItem("Assets/AssetBundles/List AssetBundles %#l")]
    static void List()
    {

        Debug.Log("<color=#ffff00ff>Search Initialising</color>, Please be patient");
        string assetPath = string.Empty;
        string bundleName = string.Empty;
        foreach (var assetGuid in AssetDatabase.FindAssets(""))
        {
            assetPath = AssetDatabase.GUIDToAssetPath(assetGuid);
            bundleName = AssetImporter.GetAtPath(assetPath).assetBundleName;
            if (string.IsNullOrEmpty(bundleName))
            {
                continue;
            }
            Debug.Log("Found asset: (GUID:<color=#00ffffff>" + assetGuid + "</color>) " + assetPath + ", AssetBundle: " + bundleName);
        }
    }
}