One of my flyfishing mentors, Henry taught me a simple fuzzy nymph tied on a hook with varied colors of fur and different ribs of tinsel or wire. I had fished these flies with Henry and his brother Les for about 2 years
and learned a lot about presentation.
Here is one of the simple Muskrat flies tied on a Mustad 9672 #12 with black monocord and a medium gold wire rib.

A Mink belly fur tied on a 9672 #16 with orange monocord and a small silver wire rib.

Here is the box finished today with a supply for testing this year tied on M9672 12s & 16s...

Furs from left to right...
Muskrat, Beaver, Dyed Mink, Dyed Rabbit, Black Beaver, Natural Mink Belly
Each row from top to bottom is ribbed by either...Gold Twist Thread, Gold wire, Silver Twist Thread, or Silver Wire