I tried to download themes and it seems that would be easy with ocs-url. However, it would not install via the terminal. See this thread. Install theme manually? - #12 by carsten888
So might be nice to have this option in the quick-installer.
I found the quick installer realy helpfull, thank you for that. 
Well it is strange it wouldn’t install because it did on my end , but my system is up to date, and installed the right version of quickcontrols as also was stated by @MyNameIsRichard in that topic. Also if everybody would request something because it couldn’t be installed, we might end up with a large request list , but that is only my opinion.
BTW I think you could also install a icon package by downloading the tar and using
you can also download ocs-url here :
That was already mentioned in the topic.
Quick Install can only install packages from the repos.
Unless that package is in the repos, it can’t be added.
Bloat.