AssetSet.cs

public abstract class AssetSet : ScriptableObject { }
public abstract class AssetSet<T> : AssetSet where T : Object
{
    [SerializeField] protected List<T> _items = new List<T>();


    private Dictionary<string, T> _dictionary;
    public string TypeName => typeof(T).Name;
    public const string CAN_NOT_FIND_WARNING = "{0} could not find {1}";

    public bool TryFind(string itemName, out T value)
    {
        return this._dictionary.TryGetValue(itemName.ToLower(), out value);
    }
    public T Find(string itemName)
    {
        this._dictionary.TryGetValue(itemName.ToLower(), out var value);
        return value;
    }
    public T FindOrFirst(string itemName)
    {
        return this._dictionary.TryGetValue(itemName.ToLower(), out var value) ? value : this._items[0];
    }
    public T Find(string itemName, bool ShowWarning)
    {
        if (!this._dictionary.TryGetValue(itemName, out var value) && ShowWarning)
        {
            GameLog.LogWarningFormat(CAN_NOT_FIND_WARNING, this.TypeName, itemName);
        }
        return value;
    }

    public virtual void OnValidate()
    {
        var names = new List<string>();
        foreach (var item in this._items)
        {
            if (item == null) { continue; }
            if (names.Contains(item.name))
            {
                GameLog.LogErrorFormat(this, "{0} has multiple objects with name '{1}'", this.name, item.name);
            }
            else
            {
                names.Add(item.name);
            }
        }
    }

    private void OnEnable()
    {
        this._dictionary = new Dictionary<string, T>();
        foreach (var item in this._items)
        {
            if (item == null) { continue; }
            var key = item.name.ToLower();

            if (this._dictionary.ContainsKey(key))
            {
                GameLog.LogError($"Dictionary '{this.name}' already contains key: '{key}'. Existing item: {this._dictionary[key].name} New Item: {item.name}");
                continue;
            }

            this._dictionary.Add(key, item);
        }
    }
}

LabelAssetSet.cs

[CreateAssetMenu(fileName = "Label Set", menuName = "Asset Set/Labels")]
public class LabelAssetSet : AssetSet<WeaponPositionLabel>
{

}

MyBehaviour.cs

public class MyBehaviour : NetworkBehaviour
{
    public LabelAssetSet AllLabels;

    [SerializeField] WeaponPositionLabel _currentLabel;

    public WeaponPositionLabel CurrentLabel
    {
        get => this._currentLabel;
        set
        {
            // only set sync var on server
            if (this.isServer)
            {
                this._currentLabel = value;
                this.currentLabelName = value.name;
            }
        }
    }

    [SyncVar(hook = nameof(onCurrentLabelChanged))]
    string currentLabelName;

    void onCurrentLabelChanged(string _, string newValue)
    {
        this._currentLabel = this.AllLabels.Find(newValue);
    }

    public override void OnStartServer()
    {
        this.currentLabelName = this._currentLabel.name;
    }
}