I just wanted to say that it would be a mistake to think that icons alone are the way forward in LibreCAD or any complex application. Yes, the icons need to be clear, but I think they should also serve as a que to learning the keyboard shortcuts - keyboard shortcuts are the way to draft effectively and quickly. Icons are a learning aid and aid in exploring the options.
As such I've added a Feature Request to add keyboard shortcuts to the icon tool tips:
https://sourceforge.net/tracker/?func=detail&aid=3525897&group_id=342582&atid=1433847
IRC: duncan-nz
Twitter: @BIM_DK