This is my main PC with a graphics card little too overpowered for the CPU. The processor cooler is also a cheap 20€ basic cooler which doesn't have a bracket behind the motherboard (that's the reason why I chose that cooler). I will be upgrading the cooling solution to a more powerful air cooler or maybe an AIO water cooler. The 20€ backplateless cooler will be used in some of my builds I make for fun out of used parts.
I don't have a specific color or light theme but I have chosen some reasonably priced RGB parts. I have a RGB fan on my psu, which is useless but I got it for so cheap (was never used) so I bought it. My gpu is founders edition, so it has a green LED.