When only printing with one nozzle on the Flashforge Creator Pro or similar printer, you can improve print quality considerably by removing the unused heavy extruder stepper motor. Doing so will reduce the weight of the carriage and help to reduce ringing and ripple artifacts on your print. It is much easier to remove the right stepper, so usually you would do single extrusion prints with your left extruder. However, the right stepper motor is also used to trigger the X endstop, so if you remove it, you must put something in place. I like the dummy stepper by race12001, but still found it too large, therefore I made this more minimal but still sturdy version that is just large enough to trigger the switch. It is easily mounted with the same screws as the stepper.
I provide two versions, one that accepts 5x5 mm M3 brass inserts, and one with direct holes. The brass inserts are recommended, but simply threading the screws into the direct holes should also work, although you risk stripping the holes if you regularly mount and unmount this part.
Another variation omits the extra tab that covers the hot-end hole. This tab may help to avoid that dust or dirt ends up in the hole, although this wouldn't be a problem if you also unscrew the right nozzle when not using it.
Temperatures can get pretty high around the carriage if you print with ABS or other materials, so in that case you may want to print this with ABS or PETG.
If you want to install the brass inserts, use a soldering iron or something else to heat them to a temperature that melts the plastic. Then push them into the block against a flat surface. Check with a long M3 screw that they are sufficiently straight, and correct if necessary.