Over the years, when people reach out or ask about potentially applying to PhD programs, I've recommended the following resources. Some of these links include extensive guides, thus this page is rather limited.
Neil Bendle's Application Guide: Marketing PhD Applications | Marketing Thought Great stuff here.
Scott Cowley's Application Guide: www.scottcowley.com/marketing-phd Another awesome resource.
The American Marketing Association's (AMA) Who Went Where (WWW) Survey of PhD graduates: https://www.ama.org/who-went-where-survey/. The WWW provides great info on market outcomes, including salaries, teaching loads, and research resources (all of which you should care about greatly if going into marketing academia).
UT Dallas Rankings of Business Schools (searchable by journal). Journal ranking matters a lot for business schools, probably more than most other fields (e.g., to get hired as an assistant professor you need X A-level revisions [R&R's at UT-Dallas, FT50, etc. journals] at a given school). As a result, you the applicant should care about a school/advisor's productivity and ability to help you develop working papers that have a chance of getting R&R's and publications at A's.
Marketing Big 15 Journal Rankings: