I also like https://www.system-rescue.org/, it also has a menu entry that will detect and boot into installed Linux systems.
Remember that you can use Ventoy as a super simple method of using these tools. Ventoy will prepare a flash drive with a tool that, when booted, will give you a menu of all the ISO images on the drive and lets you boot any of them. You can have a drive with a collection of rescue tools, install ISO's, whatever you want, and it's as easy as dropping the ISO's on there. You can also use that partition to store your own files or whatever you want, it doesn't mind.