There is no metaphysical reality, only a physical ontological reality.
I prefer Buddhist thought over the term Buddhist philosophy. Philosophy is the study of the nature and meaning of existence, truth, good and evil, etc. It suggests a passive approach to the topic, not necessarily leading to action. Thought is a way of thinking that is typical of a particular group, period of history, etc. It suggests that decisions have already been made about the nature and meaning of reality and one is acting upon these decisions.
The Buddha saw that reality was suffering or unsatisfactory in nature (dhukha), that the root cause of unsatisfactoriness is thirst or craving, that unsatisfactoriness can be overcome by eliminating craving, and that there is a systematic way to do (the eightfold path). There was nothing magical about what can be achieved. Buddhism is a straightforward way to a satisfying life.
Early Greek philosophers and philosophies were similar to Buddhism in nature, emphasising living in accordance to the understanding. It was only later that philosophy tended towards an ideal and armchair-like approach, having less to do with how one lived and more about just correct thinking.
Does something come into existence because they are thinkable or are thought of?
There is a difference between the existence of thinker and the possible existence of the thinkable object.
In fact, for something to be thinkable there needs to be a thinker for the potential act of thinkability.
To think is to imply there is something to do the thinking. All actions are done by something.
This is true of qualities and relations as well. There need be something to embody the quality. And there need be things to relate to each other.
Without a thinker there are no thoughts and thinking.
The number of thoughts one has does not increase the number of objects in existence.