Skystars F4+KO50 is an affordable stack for freestyle and racing drones. The flight controller with F405 processor has 16MB of memory for blackbox and 5V/3A as well as 10V/2A BEC. The unit also has a connector for both DJI FPV and OSD connections, so it can be conveniently used on a drone with both digital and analog video transmission. The pads for connecting the LEDs in the corners of the unit are also nice. Comes with a 50A ESCs with BlHeli_S firmware.
The second version will offer a integrated barometer, larger 16MB blackbox memory, and a USB-C connector.