PC component idea: a component that has build in memory that you can load up with a disc image file and have a software or hardware switch that you can use to have your BIOS detect whether it is in a DVD drive mode or Floppy risk drive mode so you can virtually mount ISO images for example and boot off of that device...

Niece but pls someone make

Buy an FPGA and get to it

Search bmc (baseboard managment controller) or IPMI

Already exists: iodd.kr

Update: probably should have mentioned this but yes I know USB's do this but it would also double up as local FL data backup that can be booted and reinstalled right from the BIOS and would allow easier distro hopping and OS re-install without having to find a USB (I have spent more money on USB's because I have lost them than I am willing to admit publicly)

PXE boot?

@gronostaj completely forgot about PXE .-.

By the way, if you're using UEFI (you probably should at this point) you can simply grab a large flash drive, create a bunch of FAT32 partitions on it and simply copy ISO contents to those partitions (one per partition obviously). Windows won't like it, but you can make it work by assigning drive letters with diskpart.