SwipeWell - The only tool dedicated to helping you save, organize, and reference marketing examples (so you never feel stumped).
Growth.Design Case Studies - Product tips… in a comic book format
AppGrowthLab (by SplitMetrics) - 55 app growth lessons from 30 app marketing experts
Indie Hackers - Connect with fellow entrepreneurs, developers, and bootstrappers who are sharing the strategies and revenue numbers behind their companies.
Growth Tower App Analysis - Top 500 US iOS apps & ASO analysis
Kickstart Side Hustle Newsletter - Dwarf-size newsletter with viral marketing case studies