AssetDatabase.GetAssetPathsFromAssetBundle

Description

Returns an array containing the paths of all assets marked with the specified Asset Bundle name.

All paths returned are relative to the project folder, for example: "Assets/MyTextures/hello.png" will be returned if "hello.png" has been added to an Asset Bundle.

using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

public class GetAssetPathsFromAssetBundleExample : MonoBehaviour
{
    [MenuItem("APIExamples/GetAssetPathsFromAssetBundle")]
    static void GatherAllAssetsInAssetBundles()
    {
        string[] allAssetBundles = AssetDatabase.GetAllAssetBundleNames();

        List<string> allAssetsInAnAssetBundle = new List<string>();
        for (int i = 0; i < allAssetBundles.Length; ++i)
        {
            var curBundleName = allAssetBundles[i];
            var assetsInCurBundle = AssetDatabase.GetAssetPathsFromAssetBundle(curBundleName);

            allAssetsInAnAssetBundle.AddRange(assetsInCurBundle);
        }

        //allAssetsInAnAssetBundle now contains all assets that belong to an asset bundle
    }
}