A few years I had an interesting experience. I was on a beautiful river full with trout and grayling. Fishing was ok but something was not like I expected. I changed a lot of flies nothing was ok (dries and nymphs). When I changed on spiders ( some old tied flies ) everything was different: fish over fish and big smiles on my face. From that moment I carry all the time a box with wet flies.
I'm curious which are your favorite models because I want to add more in my box:)
Here is what worked for me in that day:
I tie it in yellow, orange -rusty, brown and black.