Short answer: Nescafé (Nestlé) is the most popular coffee "powder" brand in the world — especially for instant coffee. (foodnavigator-usa.com, beveragedaily.com)

Details and context:

• Instant coffee: Nescafé is the leading global instant‑coffee brand (largest household penetration and biggest consumer reach growth in recent Kantar data). (foodnavigator-usa.com, beveragedaily.com)
• Retail/ground coffee is more fragmented by region: for example, Folgers is historically the top-selling ground/at‑home brand in the United States, while European markets feature big names such as Jacobs/Douwe Egberts, Lavazza and JDE Peet’s brands. (statista.com, en.wikipedia.org)
• Industry note: the largest coffee companies (Nestlé, JDE Peet’s and increasingly combined groups like Keurig Dr Pepper/JDE assets) control much of global branded coffee distribution — but brand popularity still varies a lot by country and format (instant, ground, whole‑bean, pods). (beveragedaily.com, reuters.com)

If you meant a specific category (instant vs. ground vs. single‑serve pods) or a particular country, I can give a short ranked list for that category and market.