Guinea feathers, black with white spots:  I've never used them, but I've seen patterns that called for them on a streamer "cheek" or just as a streamer eye (just use a bit with the black surrounding one white spot - kind of like a jungle****feather).  I'd bet that you could use them for a spidery, old-school type wet fly too (you only wrap a smaller, webbier hackly like partridge around the shank about 2 times) as in a "partridge and orange" and a "partridge and green" - they work.
 
I also have to second Dano's suggestion of pickett pins - they're great.  I use smaller ones with a bead head as nymphs or wets.  I have friends that use bigger ones like streamers.  I've heard that they work on top also.