GrowthHackList - 100+ curated growth hacks for makers + early stage startups
100 Days of Growth - Proven ways to grow your business fast (eBook)
Growth Hacking Sourcebook - The ultimate growth hacking sourcebook
Petit Hacks - Acquisition, retention, & revenue hacks used by companies
Tiny Marketing Wins - Get a (small) marketing tip every day
Responsible - Strategies to help build trust and retain users early on