Nowadays the US dollar is too much expensive to buy. I'm looking for a way to buy Thai Baht directly from Brazilian real).
So is there any company that offers a Thai Baht travel money-card (Visa Travel, American Express, etc.)?
I think your best bet is to just bring cash in Reals and buy a "money card" in Thailand. You would either have to convert the currency to Baht first, or you might be able to just buy the card from the place you exchange (depending on where you exchange, if at a bank, they likely would have some kind of card you could get).
You may also want to explore credit card options. Capital One has the Venture cards which charge no fees for international usage, you just use the card like normal and it automatically converts the transaction by itself, and you don't pay anything extra other than the cost of the thing you bought.
I'm not sure if this specific card is available to Brazilians, but if you look around you can probably find something similar. I have used this on a few trips to Europe and avoided even the exchange fees because I didn't even have to change cash, I just bought something for 10 Euros and it charged my card $13.30 (current exchange rate).