kde-icons-mono software package provides monochromatic icons theme, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install kde-icons-mono
kde-icons-mono is installed in your system.
Make ensure the kde-icons-mono package were installed using the commands given below,
$ sudo dpkg-query -l | grep kde-icons-mono *
You will get with kde-icons-mono package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | KDE |
| Package | kde-icons-mono |
| Version | 4:15.08.2-0ubuntu1 |
| Description | monochromatic icons theme |
| Sub Section | KDE |