When fishing in Oklahoma, no matter where....Lower Illinois, Blue River, Lower Mountain Fork....I have several flies that are the key goto's and that routinely stay stocked within my box.
1. Bead Head Gold Ribbed Hares Ear - both in natural and olive green (the latter more lovingly known as a Beavers Bend special). I seem to go thru more 14 and 16s in these.
2. Woolly Bugger - Whether they be Black, Olive, Brown, Rust or White these seem to be able to draw strikes when nothing else is working...key is get deep and work it slow...10s and 12s usually do the trick.
3. Pheasant Tail - another key goto pattern while similar to the hares ear...just pulls hits when the others aren't working. 14s-20s seem to work here.
4. Parachute Adams/Adams Dries - when they are sipping the surface and the hatch is on these seem to catch a majority of the action for me. 14s - 20s have worked for me.
5. Midges - various flavors and colors, used on their own or as a dropper are almost always a hit. The smaller the better seem to do the trick.
6. Scud - gray or olive have worked for me 18s - 20s get replenished the most.
7. Prince - certain days at the Lower Illinois, this was the only fly that could entice a strike 14s - 16s are the sizes i have to order the most.
8. San Juan worms...Red and Brown usually with a bead, larger the better usually use these with faster flows and deeper water and gives a larger target.
I have various and sundry other flies, however these are the ones that get replenished most in my fly box. I also plan on trying some soft hackle wet flies this year. Will be good as i just never have tried them.