Not a whole lot (not much water up here in the mtns of CO). But I've lost a few ... none that important.
The two I remember the most:
Original Ontario Roc ... in the CO river at Palisade River Bend Park (where CO State Championships will be next weekend)
1st Run Buzzz ... in the CO river at Palisade River Bend Park
The Lady of the Lakes at Spring Valley and Bear Branch has been a harsh mistress...
If I had a disc for every disc I lost, I'd have all my discs back...
To answer your question, easily 50 total of all sorts of molds.
Most recently a Champion Sidewinder