I was introduced to a multi-boot device back on 10 January 2015 by a post made on this website by gauchocollie. It was MultiSystem http://liveusb.info/dotclear/. I have used it since then on several USB flash drives at our installfests in Tempe and Sierra Vista. An AZLOCO and CLUG member and I were talking recently and he asked me if I had tried Ventoy https://www.ventoy.net/en/index.html. I tried it and it is easier to use and update than MultiSys. The features are listed on their website.
Just download the latest version, extract it, open a terminal, and follow the instructions on the document page. It is free and open source software and will work on Linux and Microsoft. Plus 90% of the distros on DistroWatch are supported. That is over 580 ISOs. If you are tired of carrying around multiple flash drives try this. You may find it useful.