The first three pics are coming from TF2 itself, but the other three are someone's fanarts: 1 - a work by @ramida-r 2 - a work by @ciorane 3 - a work by @leonifa

I bet my last pants that no one has ever asked these artists for a permission to use them, let alone sell anything with their printed works. I hope I don't have to explain why it's unethical. I can't imagine how would it feel like to find my work being used for someone's profit. You, as a fan and/or a customer, should be aware of it too. If you wish to get some fandom merch - it would be best if you'd by it directly from artists (which, by the way, will probably have better colors and resolution on prints) or make/print it yourself. Not only it's more ethical, but it's also just more rewarding to know that you either made a thing or helped someone who made a thing. Art festivals and markets, where you may acquire prints from the various artists, are also just very fun to visit - making friends and experiences in the process.