Polybus introduces a comprehensive suite of customizable Xilinx FPGA Test Patterns, comprising over 400 patterns designed to rigorously test FPGA internal functionality and interconnects. Aimed at maximizing system reliability, these patterns are useful for in-system testing, enhancing the ability to identify handling issues and ensuring upgradeability. Customized for various systems, the patterns can be run on chip testers as well, optimizing the prescreening of FPGAs beyond standard tests.