Xilinx and their partners produce lots of FPGA content that's focused on how to use these devices, but unless one wants to rely on available FPGA boards/modules, its also fundamental to be able to design FPGA boards. Xilinx has thousands of PDFs available that cover pretty much every FPGA aspect, but it would be nice to have a series of introductory webinars that highlight the key aspects of FPGA PCB design