Apps with 'Create Multiboot USB' feature
YUMI (Your Universal Multiboot Installer), is the successor to our MultibootISOs. It can be used to create a Multiboot Bootable USB Flash Drive containing multiple operating systems, antivirus utilities, disc cloning, diagnostic tools, and more.
Multisystem is an awesome tool created by LiveUSB.info, that works similar to our Windows based MultiBootISOs USB creator, but was created for use within Linux.
Ventoy is an open source tool to create bootable USB drive for ISO files.