Unity has a "Files & Folder" lens (place) to search for recently used files or folders but it can't be used to search for files or folders you've never accessed. But there's a brand new Unity lens developed by David Briscoe called "Unity Place Filesearch" that you can use to search any files or folders on your system.
Unity Place Filesearch can also be configured: you can set what folders to be included in the search (by default it's only your home folder) as well as what to ignore. Personally, I find this a lot more flexible and useful then the default Unity Files & Folders (if you do too, you can even remove the default Unity Files & Folder lens).
Install Unity Place Filesearch
To install Unity Place Filesearch, open a terminal and copy/paste the following commands:
sudo add-apt-repository ppa:pydave/unity-lenses sudo apt-get update sudo apt-get install unity-place-filesearch
Then you need to run the following command for the new lens to show up:
You can also configure which folders are used for the search results or blacklist some folders. For this you need to edit the ~/.filesearch.cfg file (it's a hidden file in your home folder) - to edit it, open a terminal and run the following command:
Configuring this file is pretty obvious: add comma separated list of folders to search on line 3 and folders to ignore under "[ignore]". Once you configure everything, run the following commands:
killall unity-filesearch-daemon setsid unity
If for some reason the new folders are not picked up by Unity Place Filesearch, restart your computer.
Report any bugs you may find @ Unity Place Filesearch Launchpad page.