Order of Naturalists

The study of the arcane doesn't fulfill the needs of all wizards whose search for knowledge never ceases, so some choose to learn from nature or decide to take mother nature's power as their own and try to bend it to their will. Naturalists learn druidic spells by studying and testing the laws of the natural world with their intimate knowledge of different kinds of magic. Some naturalists are viewed as a different circle of druids, whereas some are regarded as a threat to the balance of flora and fauna.

Druidic Knowledge

Beginning when you select this tradition at 2nd level, and whenever you gain a wizard level, you can replace one of the wizard spells you add to your spellbook with a spell from the druid spell list. The spell must be of a level for which you have spell slots. Additionally, you learn to copy druid spells into your spellbook following the same rules you normally would for copying a spell into your spellbook.
Any druid spell you gain from this feature is considered a wizard spell for you, but other wizards can’t copy druid spells from your spellbook into their own spellbooks.

(You can't learn druid cantrips this way)

Nature's Secrets

At 2nd level, you gain proficiency with the Herbalism Kit and in the Nature skill, if you are already proficient in the Nature skill you gain expertise. Additionally, you learn a druid cantrip of your choice.

Familiar Companion

At 6th level, you add the find familiar spell to your spellbook, if it's not already there. When you cast Find Familiar you may choose from an extended list of beats.
(Your DM may allow more creatures, or regulate the number of creatures you can choose from)
At 14th level the list of beasts you may choose increases an additional time.

Your familiar can serve you as a mount if it has an appropriate form. While mounted on your familiar, you can make any spell you cast that targets only you also target your familiar.
Additionally, if your familiar is subjected to an effect that allows it to make a Dexterity save to take only half damage, it takes no damage if it succeeds and half damage if it fails.
You have advantage on dextery saving throws made to avoid falling off your familiar.
Finally, mounting and dismounting your familiar costs you only 5 feet of movement, rather than half your speed.

Extended list:

CR0:
baboon, badger, deer, eagle, giant fire beetle, goat, hyena, jackal, scorpion, vulture
CR1/8:
camel, dolphin, flying snake, giant crab, giant rat, giant weasel, mastiff,
CR1/4:
boar, constrictor snake, draft horse, elk, giant badger, giant centipede, giant frog, giant lizard, giant poisonous snake, ox, panther, riding horse, wolf
CR1/2:
ape, black bear, crocodile, giant goat, giant sea eel, giant sea horse, giant wasp, reef shark, warhorse
CR1:
brown bear, dire wolf, giant hyena, giant octopus, giant spider, giant toad, lion, tiger

14th level Extended List:

CR1/4:
giant owl, giant bat

CR1:
giant eagle, giant vulture

Elemental Fortitude

At 10th level, when you finish a short rest, you can choose to gain resistance to acid, cold, fire, lightning, or thunder damage until your next short or long rest. Your familiar gains this resistance also.

When a creature within 30 feet of you takes damage of your chosen type, you can use your reaction to give them resistance to that type until the end of your next turn.
You can use this feature a number of times equal to half of your proficiency bonus (rounded down), and you regain all expended uses when you finish a long rest.

Mind Merge

At 14th level, you may choose to cast a spell that's 5th level or lower and requires concentration and let your familiar concentrate on it instead of yourself. To do so your familiar has to be small or larger so its body can withstand the power of the spell. Your familiar's concentration breaks when it fails a concentration check (using its own constitution score), you command it to stop concentrating, or you dismiss your familiar. Once you use this feature you can't use it again before taking a long rest.

While your familiar is concentrating on a spell, you can still concentrate on a different spell.