Now this was new. Teo Audio makes cables with a liquid alloy of Gallium, Indium and Tin. Teo Audio admits they are only just discovering this area of signal transmission science.
These have gotten some extremely superlative reviews. Quite expensive, yes, especially the speaker cables - nearing Siltech prices. The interconnects aren’t super expensive, if short.
One reviewer does explicitly think that any solid conductor can not even begin to approach the performance of this liquid metal…