Period Tracker - Period Tracker, the easiest way to track your periods!

Katana MRP - Katana Cloud Inventory gives you a live look at all the moving parts of your business — sales, inventory, and beyond. Combining a visual interface and smart real-time master planner, Katana makes managing inventory and manufacturing intuitive.

hummingbot - Automate crypto trading with your own market making bot

ESP - C language web framework.

productboard - Beautiful and powerful product management.

The Manager's Red Book - Other Retail