There are 2 repositories under sapbusinessone topic.
Sap Business One Helper Class for developing B1 Addon
Some SQL queries I created for my business needs
Free sap business one addons
SBO-CMDLine is a handy tool to connect to Sap Business One and run commands via cmd-line. It makes it easier to run batch commands for SBO administrator and developers.
sap business one service layer login api procces with asp.net mvc