Well you need some design with your own on a good high quality shirts, hats, jackets then I will suggest you go to some professionals. Like ApparelnBags.com
Looking for tailored fit men’s custom dress shirts? Get all sorts of patterns with Arya Clothes. Contact info@aryaclothes.com to build a nice wardrobe collection. https://www.aryaclothes.com/
I know some Embroidery Digitizing websites and I hope it'll help you a lot for your custom Embroidery work. One of them is Absolute Digitizing, they also offer 50% discount on the FIRST embroidery digitizing and Vector artwork order. No setup fees. Give them a try. You can check the website's below https://www.absolutedigitizing.com/
There are many online stores available online which will do costume t-shirt. Last month my uncle ordered costume dress for one of his official events from 6ix Rhinestone online store. The dress was in very good color combination with the unique design of Rhinestone.