Product Market Fit Toolkit - Measure your product-market fit using data you already have
Viable Fit - Measure and improve your product market fit
OpinionX - Stack rank people's priorities in minutes with OpinionX's free ranking surveys.
Phey - Keep an eye on your (Upcoming) Product's subscribers/votes 📈
Startup Growth Roadmap - Get from idea to product market fit
Start on Android by Google - Developer program to optimize your app before you launch