I whipped up a rough design for an exhaust system for my Elegoo Ma 2 Pro - I'm not particularly great with cad software, so I just used Tinkercad to make it. It has a mount for a 92mm fan that I took from an old machine (p/n 166g7-a00) although I'm sure you can use another as these appear to be strangely expeive. I soldered a usb plug to the fan's cables and so I can just power it from usb rather than a PC :P I literally used duct tape to attach it to the printer in order to keep the smells from getting out, although I'd love to see a remix from somebody that knows what they're doing and come up with a better solution. Used a 4" hose for a tumble-dryer, which is routed around my room and hangs out of the window when in use. Crude, but functional.