If you truly do have osmunda...you have what could be a small gold mine. It's impossible to find these days and I have also heard of a lot of old time orchid growers rave about it. If it were me...I'd keep and use it for myself but if you're looking to sell it then your best bet might be eBay.
Or, you could just send me all the osmunda for the cost of shipping. I'd be more than happy to take it off your hands.
BTW - the coconut husk isn't rare or expensive but there is a market for it. Same goes for the sphagnum but most orchid growers will want to know the grade (ex long fiber triple A, lesser grades of A, and/or peat type sphagnum) of it and where it's from (ex - NZ, Chile, American, etc) and w/out that information, many orchid growers won't buy it. You could still find buyers in other markets but most orchid growers tend to be pretty picky about the types they want.