If you want originals, Juergen is your man. They only come in 19 mm, though. Open-ended, don't taper.
Finertimes has both Bund style and Bund repros. Bund style come in 20 mm only, quality is even better than original Bund, taper to 19 mm at bead-blasted buckle. Unlike Bund, they're not open-ended.
Bund repros are of very good quality, open-ended and come in 18, 20 and 22 mm. Don't taper, and have shiny buckles.
I recommend both sources unreservedly.