I carry no "dedicated" fishing gear. I do however carry the following "multi-use" items which would be very effective for fishing.

5 Very tiny bait hooks: In addition to their intended purpose I have used them as sewing needles (since I don't carry dedicated sewing needles).
1 Large (3") Gaff Hook.
16' waxxed green 100# test Fireline
5' Black 550# 7 Strand Paracord
5' Blaze Orange 300# Nylon Cord
48' Black #69 Thread 10# Test

I also have used a speedhook and it is awesome but I do not keep it in a pocket kits due to its size.