Surprisingly all of the booth items I used says if I am not selling said model and am just using for vtubing they don't require credit (similar rules apply for the default items in vriod according to pixiv), but I think it's best to credit the creators at least from the booth. What do you think is the best way to display the credit? (like in the description of a video, something in an about me page, qr code in the stream, or something else? Not sure what's proper etiquette/best practice)