Asynchronous rsync with Emacs, dired and tramp.
tmtxt-dired-async by Trần Xuân Trường is an unfortunately lesser known Emacs package which extends dired, the Emacs file manager, to be able to run rsync and other commands (zip, unzip, downloading) asynchronously.
This means you can copy gigabytes of directories around whilst still happily continuing with all of your other tasks in the Emacs operating system.
It has a feature where you can add any number of files from different locations into a wait list with C-c C-a, and then asynchronously rsync the whole wait list into a final destination directory with C-c C-v.