I've played both TL 1 and TL 2. Playing TL1, there was an ultimate fishing mod where you could basically fish for almost any monster in the game, even bosses. There were several new types of fish introduced which corresponded with the new monsters. It even allowed you to find fish for the classes as pets although they were somewhat limited I think and would causes problems when trying to change them to a new pet.
I know there are mods that add new pets including the characters. However, I am a huge random chance enthusiast and prefer I don't know which pet i'm going to be stuck with for the entire game until I fish for it first thing after character creation. I would love to see the fishing mod either ported over or recreated for TL2. I'm hoping someone has connections to the guy that made this or can make their own.
Darkfirebird's Pets mod - Darkfirebird
Note this also added a crap ton of new classes. Those would just be a bonus I guess since I can get new classes for TL2 now. However having them all in 1 file is really helpful.