I made a site where you can see various godot UI themes in action and then grab them to use in your game.
https://danielkinsman.gitlab.io/godot-theme-browser/
It may melt your cpu a little bit on first load but it will finish eventually, at least on a desktop browser.
Is that the Kenney UI pack?
All the themes used have links to their original sources, just click the “get theme” button on each demo panel. The author is also listed on the top right of each panel. Though in the case of the default godot editor themes that I have included, I’m not really sure exactly where they came from or who made them…
Intrestingn, it may need some fine tuning in the design tho 
