some USB IDs to use that likely won't cause issues because fuck paying for them:
045e:ffff - the default ID used by Windows CE devices connected in mass storage mode, didn't have special drivers
046b:0001 - it's been a while since AMI made keyboards
0483:5721/5722 - used for STMs USB demo code
04d8:000a - Microchip, used for USB demo code
there's a bunch you could use without many issues