Q:

How to put gameObjects into the list?

I have gameObjects and I need to put them to the list, something like that:
List<GameObject> unityGameObjects = new List<GameObject>();

A:

You first create your list.
List<GameObject> unityGameObjects = new List<GameObject>();

You need to have a reference to the GameObject you which to add to the list. You can do this by looking for the GameObject or by creating a new instances of it.
Looking for the GameObject
GameObject g = GameObject.Find("NameOfGameObject");
unityGameObjects.Add(g);

Creating a new instance
You can't call new on GameObjects because they are MonoBehaviours but you can instantiate them from a prefab.
GameObject g = Instantiate(prefab);
unityGameObjects.Add(g);

A:

I found the solution for my question, thereby I'll ask my question, maybe it will be helpful for someone else:
 unityGameObjects.Add(GameObject.Find(unityObject.Value));

