Factory/FactorySingleton.cs

using UnityEngine;

namespace Syntriax.Modules.Factory
{
    public abstract class FactorySingleton<T> : MonoBehaviour where T : FactoryBase
    {
        public const string ParentName = "Factories";
        private static T _instance = null;
        public static T Instance
        {
            get
            {
                if (_instance == null)
                {
                    GameObject factoriesGO = GameObject.Find(ParentName) ?? new GameObject(ParentName);
                    _instance = new GameObject(typeof(T).Name).AddComponent<T>();
                    _instance.transform.SetParent(factoriesGO.transform);
                    DontDestroyOnLoad(factoriesGO);
                }

                return _instance;
            }
        }
    }
}