There's Leica copies and then fakes
The copies are really the Fed, Zorki, Tower, Leonax, Canon, Yashica, Minolta, Reid etc all based around the early II & III series Leica's some more exactly than others..
The Leica fakes are the cleverly re-worked Fed'ss and Zorki's usually to become rarer Military marked WWII Leica's. These themselves are now beginning to be collectible but I don't think I'd pay more for a fake than a genuine Leica if the same vintage. MW Classic usually has a selection of screw thread Leica's at reasonable prices.