Dark thema (dark blue), slightly transparent, with a lot of Teal-Color details, which makes this theme very pleasant and harmonious.
Also, buttons on the Panel are very interesting, as well as other small details, such as: Scrollbar, Busywidget, Slider, Tooltip ...
I suggest color scheme: "Harmony-Dark", which you can download: Here
Light version: "Harmony-Light", which you can download: Here
Aurorae Theme: "Harmony", which you can download: Here
Plasma Splashscreens "Harmony", you can download: Here
SDDM Login Theme "Harmony", you can download: Here
Kosole Color Scheme "Harmony": Here
For lovers of Breeze icons, I recommend:
Breeze Chameleon Icons Theme, which you can download: Here
-The folders change color depending on the Color Scheme you set
-It also added icons from "Papirus Icons Themes" (Only icons from the "Actions" folder)
If you want both GTK 2/3 Applications and Teal colors (instead of blue), you can download the "openSUSE-Tumbleweed" GTK2 / 3 Theme: Here