Tails
https://tails.boum.orgis a portable operating system ... Shut down the computer and start on your Tails USB stick instead of starting on Windows, macOS, or Linux.
How to create a bootable installer for macOS - Apple Support
https://support.apple.com/en-us/HT20137225.10.2021 · A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of available storage A downloaded installer for macOS Monterey, Big Sur, Catalina, Mojave, High Sierra, or El Capitan Download macOS Download: macOS Monterey , macOS Big Sur , macOS Catalina , macOS Mojave , or macOS High Sierra
Boot and Run Linux from Bootable USB | Pen Drive Linux
https://www.pendrivelinux.com25.11.2021 · The following Linux Live USB Creator software tools and utilities can be used help you quickly make a USB Bootable. Easily install, boot, and then run Linux, Diagnostic Tools, Antivirus Scanners, or even Windows from a flash drive. YUMI - Multiboot USB Creator. Universal USB Installer - Boot from USB. Write ISO to USB - Win32 Disk Imager.
Slax Linux - your pocket operating system
https://www.slax.orgSlax is a modern, portable, small and fast Linux operating system with modular approach and outstanding design. It runs directly from your USB flash drive without installing, so you can carry it everywhere you go in your pocket. Despite its small size, Slax provides nice graphical user interface and wise selection of pre-installed programs ...