Dsssox13 and Wetworth
Good question, flies can be pretty confusing. One good way to get a handle on different patterns is to take a look at the different categories of flies (dry/wet/nymph/streamer) in the fly pattern section of a big online shop like Orvis or Cabelas so you can start to recognize different ones.
But here are some examples of dries and wets and some things that you can look for on your flies to tell the difference without dumping them all in a bowl to see which ones float.
Traditional dry flies generally have lighter wire hooks and have stiff hackle collars and many have stiff tails that help them ride on the surface. Some modern dry fly patterns like ants or grasshoppers may also be made out of foam, or have wings made from an arc of deer hair, or a synthetic like Poly. And there are some dry fly patterns called Parachutes where stiff hackle is horizontally wound around the wing like a the rotor on a helicopter (instead of the more common style collar of stiff hackle wound vertically around the hook shank like the propeller on an airplane.)
Some popular examples of dry fly patterns are Adams, Elk Hair Caddis and the Royal Wulff. Here are some examples of some flies that forum members have tied in some of our fly swaps:
Some dry flies- note the light wire hooks and stiff hackle:
Here's a dry tied called Nico's Favorite tied by member Jbbfly (Jean Paul from France). Note the stiff hackle and tail:
Here's an Elk Hair Caddis (dry fly) tied by member Luked
Some wet flies-- note the heavy wire hook, and "soft" webby hackle collar on this Reid's Assassin tied by member Blue Dun:
and on this Nimmo's Killer (wet fly) from member ChrisinSelwynNZ (in New Zealand)
and on this winged wet fly, a Lead Wing Coachman tied by member Pocono
Other types of fly patterns are more obvious that they'll sink like this Gold Ribbed Hare's Ear Nymph tied by member Brandy:
Hope this helps--- and feel free to post pics of any flies you're not sure about -folks on here can probably give you a good idea of what you have.