Unfortunately, there’s not a do-it-this-way-and-your-problem-is-solved answer. but I’ll give you my view on it and how I approach it.
First, I don’t look for outside inspiration on how to handle the idiosyncrasies of a brand design project. Every situation is different, so I handle each with those idiosyncrasies in mind while working within the budget for the job.
If the brand-development budget is five million dollars, multiple style books and examples of every possible scenario from video to websites to designing the paint job for their corporate jet might be in order. A thousand-dollar job for the mom-and-pop grocery store down the street is an entirely different situation that requires working within that budget to provide them with the basics of what they’ll likely need.
For example, let’s take a fashion brand since you mentioned it.
First, what’s the budget? The budget is a tight parameter that affects everything that comes after.
Second, what look would be appropriate to evoke the appropriate emotional responses from prospective customers? Is it a budget-conscious retail company or a trendy, style-conscious company, or something else? Are their products aimed at trendy teenagers or older and more practical women or men? Do they make niche boutique products or mass-produce clothing for department store sales?
I could go on, but you get the point — really analyze the company, its products, its customers, its vision, and its goals, then design a practical brand that will work for those things.
Speaking of being practical, that’s also a huge consideration. If their brand exists almost entirely online, design for that first with an eye to how it would carry over into other mediums and situations as needed. If the brand will primarily communicate to customers through shelf appeal in a store, design for that, with an eye to how it might also carry over to their website or advertising.
I could go on with this too, but again, you get the point — think through every aspect of the problem before you begin coming up with ideas. Ask your client dozens of questions about all the things I’ve mentioned. By the way, I’m not suggesting that they collaborate on the design; I’m suggesting they collaborate with you on thinking through and answering your questions.
Your inspiration will come from carefully defining the problem, not looking through endless online searches and magazines hoping to find similar approaches that fit your project’s unique needs.