Since Duels from the Deep is coming out in a couple of weeks, I thought I should post my shark deck so that people on here can call me out on my shitty deckbuilding choices before I take it to locals.
The main combo you want to go for is 2 Toads + UDF, which you can get with any 4 bodies. Abyss Shark and Nettle lock you from doing it, but Abyss Shark increases the consistency of the deck by a lot and Nettle gives you a lot more grind, so you can't really go without them. You usually have a minimum of Toad + Kragen, which is a pretty decent board and it gives you an immense amount of followup.
I'm not playing C101/C104 or CNaphil because I think the package takes too much valuable ED space for the mediocre payoff . For this same reason, I'm also not playing Lantern Shark, as its main purpose imo is being summoned from the deck with Buzzsaw to make a rank 5.
Some advice:
If you can only make 1 Xyz and you're playing blind, go for Kragen, unless you have Buzzsaw in the GY, in which case, go for Toad for the followup.
Kragen's floating is extremely strong and can help you a lot going second. Don't be afraid to purposely crash it into your opponent's monsters to get 2 quick non-targetting pops per turn or a free UDF. It can also attach Toad from the GY to get lots of advantage.