UIFlat Plasma themes to match the UIFlat colors that can be found here:
https://store.kde.org/p/1306469

There is two Transparent Plasma themes here to go with the UIFlat color schemes.
The Regular UIFlat matches the lighter two color schemes and the UIFlat-dark matches the darker two color schemes.
I use transparency in my Plasma themes but never in my regular applications like Dolphin. I like my performance nearly as much as I like my PC to look good.
There is perfectly matching icons which are the Newaita icons that can be found here:
https://store.kde.org/p/1243493

I use some of Vinceliuice widgets but I change all the colors and the originals can be found here:
https://github.com/vinceliuice/McMojave-kde