The Nocuta NH-D15 is one of the best coolers on the market, but due to it's silver and beige color scheme and lack of RGB, it doesn't fit in with a black & RGB color scheme. This RGB shroud simply slides on over the heatsink in a way that doesn't impede air flow and has been tested to have no appreciable difference in performance. When fully wired it has 7 Addressable RGB LEDs (APA102) on each side (14 total). The RGB is controlled by an Arduino nano connected to an internal USB header and using the FastLED library.
Designed to accept a 12mm wide strip of APA102 (4wire) addressable LEDs. WS2812 (3wire) can be used as well, but due to the inherent issues with not having a clock pin, it's much more timing dependent and makes it harder for the arduino to do additional tasks such as reading temperatures sensors or voltages from a motherboard RGB header (planned features).
This design was printed on a Prusa i3 using Hatchbox black PLA, and Amazon Basics translucent PLA. I was able to print with enough accuracy that the clear text/arrows inserts could easily be press fit into the main shroud using something with a flat edge and a bit of body weight, your results may vary. If the inserts are loose you also have the option of using super glue on the backing that holds the inserts together.