I suggested take any resistor ( 1M or 10K) and short circuit with a simple wire, this will make your reference 0 ohms (even you could find gold wire but might have problem to solder to around the resistence.
note: If you want 0 ohm resistance working as reference this short circuit works.
but if you planning to use as shunt resistor for mesure the voltage or current that is going through I recommend to use a thick copper wire.
Probably you should explain better what are you planning to do with this resistance?