Intersting question. It is most likely thought forms exist through consciousness. as we direct our attention we attract these thought forms which exists omnipresently (accessible to all), we become aware of them and sense them as our thought. All thoughts already exist (past, present, future). It's a matter of being conscious of them.

Try this.

Try something like gardening or pulling out weeds but before you start bring your mind to complete silence.

While maintaining stillness within your self and your mind proceed with your gardening.

Try it, really...it is possible.

You maybe able to hold this silence only for a while but you can.

Observe how within this silence you are able actually make decisions on what to keep, what to pull out, what to throw away, notice the beauty of the flowers, all without a single conscious processing called "thinking"

And if you do it enough times you will find that you can actually make decisions and "scrutinize choices" without a single thought.

In other words, you can "THINK" without the familiar activity called thinking.

So once you test this for your self & confirm that it is actually possible to work with conscious intent without the activity of thought, ask yourself this question.

Who decided that we must constantly broadcast our intension to our ego by this constant activity called thinking?

Why have we been designed this way?

I'm not looking for an answer or claim to know the answer, but there are explanations out there that will fit this question.

I'm just trying to make you look at this existence from a different perspective

thought is a more primary existence than material form and of course more etheral,
without the plan the builders would not have known what to put together,
and would you believe that our thoughts, all of them, begin additional forms,
was it the chicken, the egg or the thought, then that creates?