gnome-themes software package provides official themes for the GNOME desktop, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gnome-themes
gnome-themes is installed in your system.
Make ensure the gnome-themes package were installed using the commands given below,
$ sudo dpkg-query -l | grep gnome-themes *
You will get with gnome-themes package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | GNOME |
| Package | gnome-themes |
| Version | 2.30.2-1 |
| Description | official themes for the GNOME desktop |
| Sub Section | GNOME |