Leave rods, reels and lines to them: fly fishers match those to each other and to the water they fish. Everything here goes with whatever they already use.
Nippers, the small cutters for line, and forceps, the clamps for taking out hooks, go missing on the river, so even someone who has them is glad of another.
The gel and the powder are a pair for dry flies, the ones that float: the gel goes on before casting, the powder dries a fly after a fish.
For someone who ties their own flies. The tool kit suits anyone who does. The vise, which holds the hook during tying, is the bigger present, for someone still using a basic one.