We’ve stopped creating separate BOMS, since you can export a BOM from EagleCAD using its built-in BOM script. PCB-SGAP is a PCB spark gap (it’s not a component but a PCB trace that creates a spark gap). That’s actually combined with a TVS for high voltage protection (the TVS part number is SMBJ45CA, you can also substitute it to SMBJ43CA or SMBJ48CA, they are all fine).