Kinda small for a shark, big attitude. It's hate you and everything you stand for. It's a ball of rage. If a fishermen snags a fish it was hunting; the shark will ram his boat over and over until it sinks. This shark has a magic resistance value of 50%, meaning it avoids, ignores, or straight up refuses to acknowledge half the spells you might throw at it. Its leather is highly valued for thieves and assassins, as not only does it make some cool red leather, but because the gloves carry on some of the shark's antimagic properties- meaning your hands are less likely to trigger volatile wards or magical traps. Also if you use speak to animals on this shark and try to talk or barter with it, it will call you a racial slur and attack you anyway.
 Lemon Shark
Piss yellow medium sized shark. Stats as shark. Not too scary, but social and tends to come in packs or in a feeding freenzy. The first time it is struck in combat or hits someone else; all of the water in 40 feet in all directions turns bright yellow with a strong fresh smell. The lemon-juice is mildly acidic, stinging your eyes and causing disadvantage on all checks to see or attack underwater if you don't have acidic resistance. On the up side, any wooden boots that pass through this cloud will have a beautiful citrus finish.
 Oblivion Shark
Dark black, big, but lazy and kinda slow. This shark is said to have an orb of annihilation in place of where its stomach should be; notable as it can eat anything that fits down its throat- including fully armored submersible warriors. If pierced, the shark bleeds black nothing. This shark is most infamous for the fact that any being with a soul consumed by it seemingly does not appear in any afterlife nor can be raised from the dead- giving the theory that this shark also digests and consumes souls. For this reason, a great bounty and project of eradication has been begun by religious orders to end this threat to the immortal souls; while others protect these sharks in an attempt to give those most damned a chance to escape their punishment.
Looks like a Great White, except with even bigger teeth. Happens to actually be sentient. While not capable of speech; is extremely empathetic towards other intelligent beings, and is commonly found rescuing or helping lost marooned sailors or shipwrecked humanoids. Most commonly known for its bow- which it will close its eyes and nod its head downwards in a show of respect. Most people are still scared of them and will attack them on sight before knowing their true, helpful intentions; and as such these sharks have learned to help people sight unseen. The Merpeople ride these into battle.
 Backwards Shark
It's a shark that swims backwards. It kills its prey by slapping them with its tail until they die, then opens its mouth and sucks in the pulp and bloody water left behind. Chainmail or other forms of armor don't do anything- as this shark deals blunt damage. Con artists often sell its teeth as a "warrior's charm"- if you wear a necklace made of this shark's teeth you get -1 to attack rolls. Wearing its tail, however, will give you a bonus of +1 damage with any blunt weapon. The tail will unfortunately rot away after about a month, losing any magical properties.
 Pirate Shark
This shark likes to attack boats to steal its treasure and hoard it in the shallows. Its incredible sense of smell is tuned in to gold and silver; can even smell it through the hull of ships. Coordinates with other sharks to attack boats to get at the treasure- sinking the vessel isn't its main goal. Will ignore anyone in the water unless if they have gold in their pockets or pouches- then it will attack them to get at it. God help you if you have a golden tooth. Not actually intelligent- its more like an oceanic lesser-dragon fish. Inexplicably prone to losing one eye in battle.
 Finger-Biter Shark
Incredible small shark; only about the size of a housecat. Looks cute with a big eye and small mouth. Tends to "hunt" by lunging at incredible speeds at larger creatures and biting off small parts of them; the tips of fins, fingers dipped in the water, octopus tentacles, and so on and then dashing away to eat it in peace half a mile away in open water. Can reach absolutely ludicrous speeds with enough space to build up momentum; this is a common sight in aquariums or private collections- a small glass tank or bowl makes this fish absolutely harmless and it will simply nibble on your fingers cutely after rocketing off from the far corner of the tank.
 Gringori Shark
White shark with black highlights around its eyes and face. This shark emits a constant low hum- comparable to a church hymn or sacred mantra. The "ohm" is both a threat that this shark is coming, but also a sound of healing that revitalizes the shark after battles with its rivals. As long as you aren't bleeding, you can swim right besides this shark and enjoy its healing noise vibrating through the water without fear of being attacked. If you spend an afternoon swimming around with this shark in peaceful waters- either restore 1 extra Hit-Point OR get an extra saving throw on a disease you are suffering from, whichever the swimmer wants to recover from more.
 Bespoke Shark
These sharks aren't natural and are instead made. In order to make them, you have to find a leathery shark egg while its still in development and bring it to your own body of water with a pinch of magic dust. If you put it in a castle's moat, the shark will become long and grayscale like a knight. If you put it in a koi pond, it gains splotchy colors like a koi and stays at a small size. If you put it in a cauldron, it grows hair and becomes a witch shark. You can customize the colors by spilling ink into the water, and the shark will prefer prey with the same kind of blood as any you pour into the water which it now lives in. These sharks are fashionable pets- but they are all still wild animals. They don't view their "owners" any different then they'd view some other random creature in the water.
 Apple Shark
The worlds only vegetarian shark. It exclusively feeds on fruit carried away by ocean currents and can survive for several days in brackish waters- often swimming upriver to gather food for its young. It's not named for its color in any way; the shark has mouth-pouches used to carry food over long ocean voyages. As such, the first time one of these was speared and caught, it had a mouth full of apples. It's teeth is specially designed to cut through vegetation; attack with advantage against defenders with wooden shields. Also deals double damage against treants, dryads, woodwives, and all other manner of plant-based creatures. It's just unfortunate they aren't exactly very common in the ocean.