If you have multiple desktop environments installed on your Ubuntu, you may found that some DEs miss their badges when you are trying to change desktop sessions in Unity Greeter (login screen).
There’s a small project on gnome-look.org that contains a set of additional badges for most DEs (e.g. LXDE, XFCE, OpenBox, MATE, Cinnamon, blackbox, ratpoison, twm).
And below is before and after using these Unity Greeter badges my login screen looks like:
If you find a missing icons (e.g. LXQt in above pic.), you may report to the project page by leaving a comment.
How to install these badges:
For Ubuntu 14.04 and Ubuntu 14.10, download package unity-greeter-badges_x.x~ubuntu_all.deb that matches your OS from the link below:
Then open the .deb package with Software Center and click install.
For Ubuntu 15.04, you can directly search for and install unity-greeter-badges from Ubuntu Software Center.
That’s it. Enjoy!