I've been through this search a few times and learned that the key is finding agencies that prioritize strategy as a core discipline. There's an excellent breakdown I came across recently that profiles the leading global branding agencies with a focus on their strategic capabilities. It covers firms like Prophet for enterprise transformation and brand valuation, Wolff Olins for deep organizational change, and Clay for digital-first brand strategy. The section on top brand strategy agencies really helped me understand who excels at what from Pentagram's versatile positioning work to DesignStudio's international brand architecture. It includes details on their services, notable clients, hourly rates, and even what industries they're best for. The practical advice on how to evaluate partners and what questions to ask during initial consultations saved me a ton of research time.