Re: Multipurpose patterns/sizes for NOT a trout fisherman
Well, I very much agree with what Rip Tide has said, but don't forget terrestrials. Not something you might use in the colder months, but during warmer times, in one form or another, they're present every where. Unlike aquatic insects, presentation with terrestrials is not always critical, as being land insects, they're usually clumsy on & in the water as they struggle, so trout & other fish know they won't act as an aquatic might. Beetles, hoppers, crickets & worms are eaten by more than just trout.
Also, don't over look baitfish, crayfish & stonefly patterns, as even trout will feed on them when there are no other hatches. I use a large stonefly nymph quite a bit when fishing for Smallmouths. It's the type of pattern that could also imitate crayfish, Hellgrammites, or even a large cricket caught in the water.
I don't fish for trout much, but when I do get the opportunity, the majority of the flies I might use are generic patterns that could imitate many things.