Copying instead of moving from desktop to certain library's.

Within Windows 10/8/7 at least, there are registry changes that you can make to change the default drag and drop selections.

Set the default drag and drop action in Windows 10, Windows 8 and Windows 7
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If you prefer to change the desired action permanently without using any modifier keys, you need to apply a simple Registry tweak.

Open Registry Editor.
Go to the following Registry key:
HKEY_CLASSES_ROOT\*
Tip: See how to jump to the desired Registry key with one click.

Create a new 32-bit DWORD value here named DefaultDropEffect. If you are running 64-bit Windows 10, you still need to create a 32-bit DWORD value. Set its value data as follows:
0 - no action will be performed,
1 - by default, the dragged file or folder will be copied,
2 - the dragged object will be moved,
4 - a shortcut will be created for the dragged file or folder.
In the following screenshot, I set the default action to "copy", i.e. DefaultDropEffect = 1:Windows 10 set default drag action

Repeat the same tweak under the key
HKEY_CLASSES_ROOT\AllFilesystemObjects
Now try to drag a file or folder to some other location. In my case, it will be copied.drag action copy
You are done. You can always revert this tweak by deleting the DefaultDropEffect value. And of course, you can still use modifier keys to change the action. Or you can simply use the right mouse button to drag and drop and Windows will show you a context menu asking you what you want to do.

To avoid Registry editing for this tweak, you can use Winaero Tweaker. It allows you to set the default drag-n-drop action with just one click! Check the appropriate option under Behavior\Default Drag-n-Drop action: