The Rainbow Warrior, a Lance Egan pattern out of the Utah competition scene, is pure attractor. The body is pearl Mylar tinsel over a slim profile, with a tungsten bead up front and a short collar of pink dubbing at the thorax for a hot spot. It doesn't copy any one bug closely - it reads as a midge pupa or a small Baetis nymph, and the flash gets fish to commit.
Tie it in sizes 16-22. The pearl-pink dressing is the standard and the one to carry. Small sizes (18-22) cover midge water; 16 covers BWO emergences and bigger clear-water runs.
This is a clear-water fly. It shines in low to normal flows where trout can see the flash and the bead drops it into the feeding lane. Best when water is 40-60F. Fish it dead-drift under an indicator or as the dropper on a two-fly nymph rig - pair it below a darker, drabber nymph so the Warrior does the flagging and the natural-looking fly closes the deal. In winter and early spring midge water, it's often the fly that draws the first look.