Since you are into cosplays, I would try to find brands that fit into that niche. I wouldn’t just reach out to any company and ask for free stuff. Some companies have a page on their website that says “work with us” or something along those lines and you’d fill out an application. Some companies you can DM. I wouldn’t message them saying “hey give me free stuff”. Think of it as a job application. You’re more likely to get a partnership opportunity if you already use the product because then the company knows you actually like the product and not just asking for free things.