I had kind of found a few ideas in the past, but last week I set out to start creating a multi-boot USB drive with all of the tools I frequently use. I picked up a 32GB thumb drive that should have plenty of room. To make my USB drive multi-boot, I used the YUMI Multiboot USB Creator.
It is basically an NSIS installer that lets you select a USB drive, make it bootable, and select what ISOs you want to load. It will format it FAT32 for you if you want. (I'm not positive, but I suspect FAT32 may be required for some boot CDs/floppy images). It will even initiate the download of all of the ISOs it has in its prebuilt list. I found this really useful, though occasionally a newer version of a tool would be out and it wouldn't directly find it. It was still very easy to use. It also allows you to add unlisted bootable ISOs, which it will add to a separate list. I tested this with 2 vendor diagnostic boot CDs and they both worked - your mileage may vary with some ISOs.
A point of confusion for me was how to add MULTIPLE ISOs. YUMI Multiboot USB Creator is designed to be run once per ISO. Don't try to add all of them at once, or you may end up scratching your head for a few minutes. Add them one at a time. At the end of each addition, it will ask you if you want to add another or not. Clicking yes, or running it again will add an additional bootable ISO while maintaining any that are already installed.It doesn't currently provide a way to remove a bootable ISO, so if you accidentally load the same one twice or otherwise want to remove one, you will have to edit the menu files by hand. This does appear to be a planned feature, though, so that may cease to be the case at some point. The version as of the time of this post is 0.0.1.1 - this version came out a couple of weeks ago, so it appears to be actively in development.
Here are some of the ISOs I loaded on mine:
- Vendor Hardware Diagnostic CDs