How to stop a iCloud Drive file or folder download in OS X?
This plugin helped! - lets you select which folders to sync: https://github.com/Obbut/iCloud-Control. To download it, go to https://itunes.apple.com/us/app/autodesk-sketchbook/id883738213?mt=8 and select the latest zip file. (Right now it's at https://github.com/Obbut/iCloud-Control/releases/download/1.1.0/iCloud.Control.app.zip.) 

If it doesn't unzip automatically, unzip it and move it to your Application folder.

From the site:


Place the app in your Applications folder 
Launch it by right/control clicking and choosing "Open" (to prevent gatekeeper from preventing the app to open) and follow the instructions on screen


Usage

The following options are provided through a toolbar item in the Finder.


Remove selected item locally: the selected item(s) will be removed
from your device, while remaining in iCloud. 
Download selected item: download previously removed files from iCloud. On macOS Sierra, the cloud icon provides the same functionality. 
Publish public link: places a link to the selected file in your clipboard.


Compatibility

iCloud Control should work on macOS 10.2 Sierra, and on OS X 10.11 El Capitan.