The brightest strings I have ever tried were Thomastik Power Brights. They look rather bronzen from the metal coating or whatever they have, or maybe it is a different alloy or something.
However they feel like normal strings, pretty great ones at that to my taste and when I put them on my Crawler axe they to me seemed much brighter than the nickel ones I had on there before. Really brought what the Crawler needed.
Can highly recommend you try them.