Basic Unity singleton

Singleton.cs

    public class Singleton<T> : MonoBehaviour where T : Singleton<T>
    {
        static public T s_Instance;

        static public T Instance
        {
            get
            {
                if (s_Instance == null)
                {
                    s_Instance = FindObjectOfType<T>();
                }

                return s_Instance;
            }
        }

        protected virtual void Awake()
        {
            if (s_Instance == null)
            {
                s_Instance = (T)this;
                Init();
            }
            else
            {
                Destroy(gameObject);
            }
        }

        protected virtual void Init()
        {
        }

        protected virtual void OnDestroy()
        {
            if (s_Instance == this)
            {
                s_Instance = null;
            }
        }
    }