Example of AssetBundle object reference

AssetBundleObjectReference.cs

using System;
using System.IO;
using System.Threading.Tasks;
using Sirenix.OdinInspector;
using UnityEditor;
using UnityEngine;
using Object = UnityEngine.Object;


public class AssetBundleObjectReference<T> where T : Object {
#if UNITY_EDITOR
    private T _assetReference;

    [AssetsOnly]
    [PreviewField]
    [ShowInInspector]
    public T AssetReference {
        get {
            if (string.IsNullOrEmpty(_assetGuid)) {
                AssetReference = null;
                return _assetReference;
            }

            if (_assetReference == null) {
                // Load from AssetDatabase based on _assetGuid
                _assetReference = 
                    AssetDatabase.LoadAssetAtPath<T>(AssetDatabase.GUIDToAssetPath(_assetGuid)); 
            }

            if (!Application.isPlaying) Setter(); // Update name and path
            return _assetReference;
        }
        set {
            if (_assetReference == value) return;
            _assetReference = value;
            Setter();
        }
    }

    private void Setter() {
        if (_assetReference != null) {
            var assetPath = AssetDatabase.GetAssetPath(_assetReference);
            _assetGuid = AssetDatabase.AssetPathToGUID(assetPath);
            var bundleName = AssetImporter.GetAtPath(assetPath).assetBundleName;
            BundleName = bundleName;
            AssetName = Path.GetFileNameWithoutExtension(assetPath);
        } else {
            AssetName = null;
            BundleName = null;
        }
    }

    private bool CheckAssetReference() {
        return _assetReference == null;
    }
#endif

    [HideIf("CheckAssetReference")]
    [ReadOnly]
    public string BundleName;

    [HideIf("CheckAssetReference")]
    [ReadOnly]
    public string AssetName;

    [HideIf("CheckAssetReference")]
    [SerializeField, ReadOnly]
    private string _assetGuid;

    public Task<T> LoadAssetFromBundle() {
#if UNITY_EDITOR
        if (Application.isPlaying) return BundlesManager.Instance.LoadAsset<T>(BundleName, AssetName);

        var task = Task<T>.Factory.StartNew(() => AssetReference);
        return task;

#else
            return BundlesManager.Instance.LoadAsset<T>(BundleName, AssetName);
#endif
    }
}

// Unity does not serialise generics, the trick is to create specific classes for each type of asset you want to serialise

[Serializable]
public class SpriteBundleReference : AssetBundleObjectReference<Sprite> {
}