Viable Fit - Measure and improve your product market fit
OpinionX - Stack rank people's priorities in minutes with OpinionX's free ranking surveys.
Focus Framework - A hands on guide to find product-market fit w/ lean methods
Pioneer Launcher - Track your launch progress & find product-market fit.
Start on Android by Google - Developer program to optimize your app before you launch
Product Market Fit Toolkit - Measure your product-market fit using data you already have