Growth Hacker Marketing - Ryan Holiday's book, re-released and expanded
Viable Fit - Measure and improve your product market fit
Your Growth Hacks Aren't Working - Free new book by Steli Efti on B2B customer acquisition
Product Fit - Measure product/market fit in app with your users.
GrowthHackList - 100+ curated growth hacks for makers + early stage startups
OpinionX - Stack rank people's priorities in minutes with OpinionX's free ranking surveys.