I hear you, the most important part of getting a creative process started is just finding the right materials. If you find something you like online, textile companies are usually happy to send free samples. For the patches, I would either let people iron or sew them on Boy Scouts merit badge style. Or keep it simple. Simple always works.
@jcm3 Here are some of the headcovers made under my family’s golf brand DINGERS. I’m certainly not a headcover company / factory, and don’t care to be. With each headcover, I try to explore different materials and handcraft techniques (embroidery, patchwork, appliqué, etc). This makes for a longer and unpredictable making process, but I like it. Currently working on a 2019 Majors series inspired by the four winners. I can keep you guys posted of the process somewhere. Maybe I should start my own thread 
1-3 - DINGERS putter covers made from the curtains of my grandparents house.
4 - SHAFUA driver inspired by @MerchCzar
5 - GO ARNIE putter cover
