The fishing rod no longer just drops fish! It can drop absolutely any item in the game!
The base datapack only drops one item each time you fish, the highroller version will drop a bunch of random items each time you fish.
This pack was built on top of the vanilla tweaks "Classic Fishing Loot" datapack
(cuz im not good at making datapacks from complete scratch :P)
Credits:
Vanilla Tweaks: https://vanillatweaks.net/