Can thoughts materialize?

...According to the Buddha, the best we can do is looking objectively at Dhamma, our essential nature: knowing and seeing the sensorial world as it really is. Yathabhuta nana dassana.

Then awareness and equanimity will lead automatically to liberation of the self.

Shaila Catherine—Focused and Fearless. A Meditator’s Guide to States of Deep Joy, Calm, and Clarity (2008) p. 149:

‘When the mind is profoundly balanced with equanimity, there is no averse reaction to the basic fact that nothing in the material world can bring satisfaction.’

Then we 'know' and 'see' that 'nothing in the material world can bring satisfaction':

Samyutta Nikaya (1.168):

'The entire world is in flames, the entire world is going up in smoke; the entire world is burning, the entire world is vibrating. But that which does not vibrate or burn, which is experienced by the noble ones, where death has no entry— in that my mind delights.'

Thoughts can in fact materialize. It seems that it violates the laws of nature but it doesn't. We are only beginning to learn about how our universe works. The following website explains it in more detail:

https://sites.google.com/site/materializationbythought/home?previewAsViewer=1

When religion or dogma,or politics presses you ,especially in religion where info and symbolism is illusiimal or delusional ,this religious information of existence of evil or good deities wars and persecution,witchcraft, against you enter you,become permanent thought and will be materialized. That's why so much calamities and madness happened to people and mankind .. I was also one of that victim . People become engaged in illusions internal and external wars.. Where people wanted to find smooth medicine they found antagonistic opposition between unseen powers,and that makes people captivated

I think yes: "at least sometimes".

Imagine if you're a salesperson, trying to sell something -- it will help to be cheerful and confident, i.e. people are more likely to want to buy from you ... and you're more likely to be willing to try (and try again after each failure).

But the "thoughts" are not enough -- e.g. I suppose that whether you're a successful salesperson would also depend on what you're selling, what the customer needs, whether they afford it, etc.

There's a sutta that might be relevant, SN 42.6 -- you can't make a boulder float on a lake just by praying.

Although "state of mind" is relevant generally, see e.g. Mental factors (Buddhism).

But what you're describing might be magical thinking, which maybe isn't Buddhist.

But I think that part of the training of modern professional/trained athletes is to imagine themselves winning -- e.g. to imagine and re-imagine in detail, to foresee, to plan, what it feels like and the various details of what a body does, to run 100 meters in 9.8 seconds. That imagination is a kind of planning for the future. That's not exactly "magical" though (e.g. they'd do it as well as, not instead of, physical training) -- and some Buddhist practices (e.g. bhavana meditation, maybe tantrayana too) might be like that, analogous to that.

Many people believe that their good or bad thoughts can materialize in the future

Yes, this is called Kamma. Good thoughts have the potential to cause good consequences. Bad thoughts have the potential to cause bad consequences. But the Buddhist way of identifying a good/bad thoughts has nothing to do with positive/negative thinking. If a thought is tainted with craving, aversion and ignorance, it is a bad thought. If not, it is a good thought.

ex: Going after a mirage, thinking that it's a real stream of water can be a positive thought, if you really believe in it. But it's not going to bring intended results. Thinking that slaughtering animals and offering them to a god/demon will result in a good harvest can be a positive thought. But it is a bad thought according to Buddhism. Thinking that there's an all loving, all governing god who's going to save you from suffering can be a positive thought. But it is a bad thought according to Buddhism. Thinking about impermanence, suffering can be taken as negative thinking. But they are good thoughts according to Buddhism.

All bad thoughts have the potential to give repercussions. But not all good thoughts give future results. Ex: the thoughts of enlightened being are called Kiriya citta. You could call them neutral, but they are good since they don't cause harm.

So some people try to be always in good mood and think positively. Others are not so happy and just try not to think about bad things too often to prevent them from happening.

This is not possible! Bad and good things happen because of causes. If the causes are not present for something to happen, you simply can't make it happen, regardless of your mood. To take the same example, just because you pray to a god, you won't get the things you pray for. There should be someone listening, who is in a position to give you what you want. And that being should decide to help in the way you want.