What are some alternatives?
When comparing USB Mountr and Rufus, you can also consider the following products
MultiBootUSB - MultiBootUSB is a software to create multi boot live Linux on a removable media i.e USB disk.
UNetbootin - UNetbootin is a utility for creating live bootable USB drives. The name of the software is short for Universal Netboot Installer, and its most prevalent use has been to create bootable versions of Linux distributions on a USB drive.
YUMI - YUMI (Your Universal Multiboot Installer), is the successor to our MultibootISOs.
Easy2Boot - Flexible and configurable USB drive multiboot solution which also supports UEFI booting.
Etcher - Why Etcher? Here at resin.
DriveDroid - DriveDroid allows you to boot your PC from ISO/IMG files stored on your phone.