Quantity   Component name
1 × TORX T6 screwdriver To take apart the controller.
4 × mini PCB momentary switches "12*12*4.3MM Quality Mini PCB Momentary Tactile Push Button Switch SPST LW". These were the thinnest tactile buttons i could find on Ebay, 10pcs for $1.19.
1 × old iPhone charging cable Dissected to get the thin wires.
1 × soldering iron With a sharp tip to make tiny soldering and holes in plastic.
1 × solder paste Thanks god it exists, made tiny soldering so much easier!
1 × Dremel 2000 butane soldering torch Used to cut the plastic, it wasn't easy. Need to find a better tool next time.
1 × pricker To make holes in plastic.