I believe the "Tools" icon that you removed was a folder that contained some icons of useful tools.  Nothing is lost.  Just create a new folder on your home screen (or another screen), name it Tools, and put useful things from the App drawer in the folder.  When you put things in a folder they are not moved just "short-cuts" are created like a PC.  It's been a while since I had a Tools folder and I no longer remember what it contained.