ShareX would be cool to be added.
For some reason, the download page does not mention any portable version: https://getsharex.com/downloads/
However, when clicking on one, it redirects to a Github where there is a portable version. e.g. (with the latest version): https://github.com/ShareX/ShareX/releases/tag/v13.6.1
The portable version does work great. Been using it for some time.