One Month iOS - Learn to build your first iPhone app in just one month
wasp-os - Firmware for smart watches based on the nRF52 family of microcontrollers (including Pine64 PineTime)
Sjabloon - Rails SaaS starter kit (just $79 one-time)
InfiniTime - InfiniTime is an open-source, C++-based firmware OS specifically made for the PineTime smartwatch.
One Month Python - Learn to build Django apps in just one month.
Mi Heart rate - Continuous HR and smart alarm