Staying in the spirit of Ctrl keyboard features and tools, I have created a graphic showing all the out-of-the-box AutoCAD Ctrl + keyboard shortcuts.
I have verified these in AutoCAD 2014 and Civil 3D 2014 with the results as shown, and also have run most on AutoCAD 2015, with no differences noted; please let me know if your results differ.
I have done a little visual sorting as well:
Blue = Palettes and display
Yellow = File operations
Green = Toggles and Variables
Pink = Selection and Clipboard
White = No action
This is the out-of-the-box configuration; notice there are plenty of unassigned keys for your own customization!
For example, I map CTRL+SHIFT+V to _Pasteorig (paste to original coordinates), since I do this often. I try to avoid changing any default settings, with the exception of F1, which I re-map to Cancel, since it drives us all nuts when we accidentally hit the F1 key and AutoCAD launches Help.
I hope this helps you try and keep track of all the built in shortcuts; Happy CADding!
Update: FYI, Here are the out-of the box CTRL+SHIFT shortcuts:
CTRL+SHIFT+C Copy with base Point
CTRL+SHIFT+H Toggle HIDEPALETTES
CTRL+SHIFT+I Toggle Infer Constraints
CTRL+SHIFT+L Select Previous
CTRL+SHIFT+P Toggle QPMODE
CTRL+SHIFT+V Paste as Block
2015-01-06 Update: I have corrected the CTRL+N (NEW) and CTRL+M (no command) keys in the graphic