Superconductors come in different critical temperatures right?
Notice the temperature scale is in Kelvin not Celsius.
TK = TC + 273.15
Mercury is a superconductor only at around 4.2K (-268.95oC), and these temperatures require the more expensive liquid helium to cool them as opposed to the ceramic conductors which require the much cheaper liquid nitrogen (as cheap as beer) to cool them because their critical temperature is around 130K (around -136oC).
Search for any superconductors, typically the ceramic ones with a critical temperature of around the 130K mark.