well...what do you think is a "high win rate"?
There are two quite "cheap" FG-Farmers...SGs unupped FG-Farmer and RoL/Hope... just use the search function.
SGs unupped FG Farmer actually can win sometimes completely unupped... i started FG Farming with it...and i worked. Dont have exact numbers about it but it has a decent enough win rate (maybe about 25-50%) against easier FGs.
RoL/Hope is quite popular, but as i never used it, i wont say anything more about it, before i say something wrong...
But both have their weaknesses, so i wouldnt say they have a "high-win rate"...actually i dont think there is ANY deck, with really high win rates against all FGs...some decks do pretty well...completely upped, of course