We purchase RSPro filaments, mainly for prototyping, but they have proven to be good quality filaments to be fair....
We've printed using the "Copper" and "Bronze" (RSPro Filaments) - for Conductive, and Dissipative property testing. These are PLA based but claim to be 80% copper and bronze content......using CC0.6 and CC0.4 nozzles.
We also use Kimya ESD filament which is OK, but a pain to print with.
Another supplier we use, who have proven very helpful is 3DGBIRE ( https://3dgbire.com/ )
If you have a specific question, feel free to ask.....👍