This is an arcane tradition (subclass) for the wizard class in D&D 5th edition.

Some wizards use their studies to view glimpses of the future or become masters over undeath. Others however move their studies away from the arcane power they can possess and towards harnessing the powers of the magical creatures which already exist.

Magizoologist

2nd – Behavourology. Your study of the animals has given you a strange understanding of how they think. You gain proficiency in animal handling. You can add your Intelligence modifier to animal handling checks in addition to your Wisdom modifier.

2nd – Handful of Critters. Choose two creatures from the list below to gain as critters. Critters are naturally friendly towards you and will follow your commands whenever possible so long as you treat them well. All your critters have AC 15, use your saving throws, and have half the hit points you do. They are willing to put themselves in danger for you but will not perform acts that are inherently suicidal. If a critter dies, you can be replace it through an 8 hour ritual which costs 50gp per wizard level you possess.
– Pick Insect. This grey insect quickly shapes itself to fill small spaces. You can use a pick insect as a set of thieves tools you are proficient in. The pick insect has a +4 bonus to try and disarm traps or open locks without on its own. The pick insect has a speed of 25 feet and a climb of 10 feet.
– Honey Dancer. When this fluffy marsupial extends its membraned arms a magical updraft allows it to glide softly through the air. The honey dancer can also cause its tail to emit a honey coloured light. This produces bright light in a 20-foot radius and dim light for an additional 20 feet. The honey dancer has a speed of 20 feet and climb speed of 20 feet and a flying speed of 40 feet.
– Parapod. This parasol shaped mollusc catches the wind and escape predators. While lowered a DC 15 Wisdom (perception) skill check is required to notice that it the parapod is not an ordanary parasol. While expanded, the parapod and you can cast feather fall on yourselves at will, without using a spell slot. Expanding and lowering the parapod is a bonus action. The parapod has a speed of 10 feet.
– Chidllet. A spiny rodents which curls up into a defensive ball whenever danger approachs, protecting its extradimensional pouch. The chidllet acts as a bag of holding which deals 1 piercing damage to any creature, aside from you, that tries to open it. The chidllet has a speed of 30 feet.
– Tireir. The prehensile nose trunk of this black striped pig searches around your head for its next meal. The tireir consumes your lethargy and drowsiness, making it so that you no longer need to sleep. If you would be magically forced to sleep you have advantage on the saving throw. The tireir has a speed of 15 feet.
– Konie. This living leaf uses its extendable arms and legs to help around the house. During a short or long rest the Konie will repair your shoes, prepare your lunch, or wash the dishes. It can achieve any activity which can be done with either the mending, prestidigitation, or mage hand spells but takes one hour to complete its job. The konie has a speed of 30 feet.

6th – Pocket Zoo. Its always helpful to have your little friends on hand at any moment. You can designate one item with multiple pouches, such as a jacket or a backpack, to be your pocket zoo. Each pouch of your pocket zoo leads to a 8 foot square extradimensial space which acts as the perfect enclosure for one of your critters. These enclosures include a light source, an air supply, fresh or salt water, warm or cold places to lay down, and nutritious food. Only critters can be put into or taken out of a pocket zoo and all items within the pocket zoo a resupplied at the end of a long rest. You can designate a new item as a pocket zoo over a long rest, and if you do the old pocket zoo loses its magic.

10th – Right Animal for the Job. You’ve learnt the secrets of more strange and unqiue creatures. You gain one more critter and can increase your available options to include the expanded list below.
– Pipsune. A fluffy, serpentine animal which possess a features similar to a fox. Pipsune have a penchant for storing smoke in their bodies and are rarely seen without a pipe. As an action, you can order your pipsune to exhale a cloud of smoke around itself. This is identical to a fog cloud spell centered on the pipsune which doesn’t require concentration. You can use this ability a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest. The pipsune has a speed of 20 foot and a climb of 20 ft.
– Kallad. This thumb sized black bird raises its wings to form a conical shape around an open beak. As an action, the kallad can raise its wings. While they are raised its speed drops to 0 and you can speak into its beak. Any creature holding one of the kallad’s eggs can hear what you say, so long as they are within a number of miles equal to your proficiency bonus. The kallad can maintain this connection to up to three eggs during at a time and can lay one egg every long rest. The kallad has a speed of 10 feet and a fly of 40 feet.
– Ba’nealiz. A whiskered, semiaquatic mammal which seems to move and bend its body like rubber. As a bonus action, a ba’nealiz can transform parts of its body into any muscial instrument, you are proficient in any instrument it transforms into. As an action, you can cast confusion once without using a spell slot by playing your ba’nealiz. You can’t do so again until you finish a long rest. The ba’nealiz has a speed of 20 feet and a swim of 30 feet.
– Grop. This sticky amphibian is constantly looking for prey with its stalked compound eye. As a bonus action, you can squeeze your grop to shoot out its 30-foot-long spectral tongue at a target creature or object. This tongue sticks to any surface and reels itself back to the grop immediately. If the tongue sticks to an object or a large or larger creature the grop pulls you both to it. If the tongue sticks to a medium or smaller creature, that creature must make a strength saving throw against your spell save DC or be pulled towards you. The grop has a speed of 20 feet and a climb of 20 feet.

14th – Magical Menagerie. Your knowledge of magical beasts has taken on its own supernatural life. When you make a Wisdom (animal handling) check, you treat a d20 roll of 9 or lower as a 10. You also gain one additional critter and can now perform the ritual to replace a critter in only 1 hour and at no cost.
Creation Process.

One of the things my players love to do is collect pets. Tigers, t-rexes, baby dragons, and other assorted beasts are their usual targets. But, what about those small animals you couldn’t use in a fight? Kodo and Podo (The Beastmaster, 1982) help Dar steal keys or chew through ropes and Niffler (Fantastic Beasts and Where to Find Them, 2016) acts as an easy storage solution for Newt. So, what if one of your players wants to befirend a slew of magically gifted animal friends? Lets make them a Magizoologist class.