You've done pretty good so far for fly selection. The prince nymph and the pheasant tail are "generic" flies that look like a lot of nymphs in general. Another good all-around one is the hare's ear. Another option is to try the same flies in a beadhead version (they sink better) and in "flashback" versions (for a little "glitter" - makes 'em look alive, and gives the impression of "motion without movement").
These will keep you catching fish while you learn about your local flies. Don't overlook caddis imitations and stoneflies if they are in your streams.
Another good fly to keep on hand and use is a wooly bugger in colors black, brown, and olive. It's another "generic" fly and catches fish most places.
Keep at it, it's a lot of fun!