I didn't test QtEmu (first mentioned at viewtopic.php?p=21717#p21717) very much but the developer provides a 'portable' package download that proved to be not really portable -- QtEmu insisted on saving absolute paths to the registry at "HKCU\Software\QtEmu"; it also created the usual junk at 'HKCU\Software\QtProject' and a folder at '%USERPROFILE%\.qtemu'. As the backend (i.e., QEMU itself), is mostly CLI driven, it's safe to assume it'll be portable.
Total disk cost was a whopping 1.06GB all included, but I was able to launch it pretty fast.
QtEmu is a fork of an older project (still present at https://qtemu.org/) and is being developed since 2017 by a Spanish IBM systems engineer; note that his personal page doesn't provide download links, only his Gitlab page (https://gitlab.com/qtemu/gui).
QtEmu is a graphical user interface for QEMU. It has the ability to run virtual operating systems on native systems. This way you can easily test a new operating system or try a Live CD on your system without any troubles and dangers.
Download QtEmu latest release (currently v2.1, dated 2019-07-29) from https://gitlab.com/qtemu/gui.
You'll also have to fetch the latest QEMU Windows binaries (currently, v5.2.0 released 2021-02-08) from the official repo at https://qemu.weilnetz.de/w32/2021/ or https://qemu.weilnetz.de/w64/2021/.
Finally, the guide that set me in this wild goose chase for QtEmu portability is at: