Research Writing - Categories & subcategories other divisions

I am setting up an e-commerce website where I would be aiming to sell a unique line of postcards & I have high ambitions for it. I need someone with great skills to research the market and suggest creative & appropriate categories, subcategories & other divisions. You see, beside the traditional and standard categories such as Birthday, Christmas, mother’s day, Father’s day and so forth… I aim to make it more creative and explore it further, make it more specific and add additional options for the end user. Imagine you’re entering the world’s biggest online postcard retailer, what would you expect to see? Only the main traditional occasions? What would you say we should expect from the world’s biggest postcard retailer? Smaller division such as: for him, fir her? than what? auntie! Alright, then what? Maybe division by style? Like, hummer/funny, for couple, me to you, spoof, textless/image only, cute! Alright, getting there! How could we make it more special? More creative, more unique, more user friendly! This is what I would need help with. Please bear in mind that in order to ensure best quality I would prefer someone whose English is extremely good, who can research & communicate over voice or text fairly well and work with me closely to ensure our final website menu has all it should the way it should. Thanks and look forward to speaking to you on the other side.