I went through a phase a few years ago where I tried to really minimize the number of flies I carried -- especially on back country trips where space and weight are important factors. After one specific outing where I caught fish on scuds, damsels and callibaetis, I decided it was time to pick a few features on each type of bug and create a mega-bug "Chimera" style fly that had pieces of several insects. It's not so much a generic searching or attractor pattern as it is a multi-tasking bug imitator.
A high mountain Fall Brook Trout that fell to a black Chimera
I ended up spending some time at the vise and combined a few nymph styles, including a couple I stole from Cheech, and came up with this pattern. I've been fishing it now on some stillwaters and even a couple of rivers and it's done very well. The nice thing is this fly, depending on color and size, can pass as a scud, callibaetis, damsel, dragon fly or whatever else you might want to cover. What makes it even nicer is that you have a set of materials for one pattern that's tied the same, just mixing those colors up.