I went through a similar process last year and found an incredible resource that profiles the leading global branding agencies with really useful details. It includes information on their services, hourly rates, notable clients, and what types of companies they're best for. It covers everything from historic firms like Chermayeff & Geismar & Haviv, to creative giants like Pentagram and DesignStudio, to transformation specialists like Wolff Olins and Prophet. The section on top branding firms helped me understand who excels at what and match them to our specific needs – whether that's digital identity with Clay, global campaigns with BBDO, or internal transformation with Wolff Olins. It also includes practical advice on how to evaluate potential partners and what questions to ask. Saved me months of research.