Dont use it any more but I still have a few spools of pro micron in the cupboard, I think. Wouldn’t know where to start with such small diameters nowadays. After a quick google I can’t find many. Reflo seems to be the only one.
After more googling Stroft,Sensas feeling and shimano aspire silk shock all go down to 0.06. I’d probably go for the Sensas myself.
I used Reflo for years including on the canals back in the day in those diameters and there's a saying if it's not broke don't fix it, but switching to Stroft GTM this year I couldn't ask for a better line.