Ok, hear me out, a PCIe expansion card, with a bit of RAM, a translation chip, and a female 40 pin GPIO connector, like the ones on the Raspberry Pi and it's single board computer standard, It can be a co-processor to either the CPU or GPU, helping render lighter tasks, like far away textures, simple enemy AI, 2D sprites, or even something like handling sounds, and, let's get crazier here, what if also on the board was a connector for an Arduino, for very simple tasks, even too light for the Pi?
It might be incredibly stupid as I say in the title, but on the other hand, maybe not?