As @wanek mentioned, the documents pretty much sum up the various Blynk commands and functions.
As for which library to include… that is determined, as far as Blynk libraries, by the type of MCU & connection method.
I make use of the Sketch Builder and pick differing devices and connections to see the required libraries.
With the NodeMCU, or most any ESP8266, you will always need
Plus any additional libraries for extra features, sensors, etc… based on those add-ons requirements.