Growth Hacker Marketing - Ryan Holiday's book, re-released and expanded
GrowthHackingIdea.com - One short, curated growth hacking idea a day to your email
Your Growth Hacks Aren't Working - Free new book by Steli Efti on B2B customer acquisition
Ryan Holiday - We Invest $500k in Sci-Fi Founders.
GrowthHackList - 100+ curated growth hacks for makers + early stage startups
Spacedoo - Short actionable marketing hacks