Program: x64dbg
License: Open Source/GPL
Description: x64dbg is an open-source x32/x64 debugger for Windows.
Website: https://portableapps.com/node/4507
Other: If you run x96dbg.exe (instead of x32dbg/x64dbg), it creates a shell-extension for .exe and .dll-files. A .reg to remove them is linked in the FAQ. Otherwise it is fully portable
https://github.com/x64dbg/x64dbg/wiki/Frequently-Asked-Questions
If anyone has the mood to pack this one, i think it would fit great in the PA repo.