Rangers who follow this archetype have spent time in the wilds and have attuned themselves to beasts of the realm.

Beastial Aspect

During a long rest you take on the aspect of a beast. The traits of that aspect remain until your next long rest. You can only have one aspect active at a time. 

Choose one of the following during a long rest:

Aspect of the Hawk:
Add 5 to Perception rolls that rely on sight, as well as your normal perception bonus.
Ranged weapons can be used at maximum distance without rolling with disadvantage.

Aspect of the Viper:
Add 1d4 poison damage to successful melee and ranged attacks. Increase by 1d4 at levels 5, 10, 15 and 20.
Add 5 to stealth rolls, as well as your normal stealth bonus.

Aspect of the Fox:
Add 2 to your spell DC.
Gain 2 spell slots for your maximum spell level.

Aspect of the Monkey:
Add 5 to Acrobatics and Athletics rolls, as well as your normal bonuses.
Add 2 to your AC

Aspect of the Cheetah:
Add 5 to your initiative bonus
Add 15 to your movement speed

Aspect of the Chameleon:
Once per long rest, you can become invisible, but must remain completely still to uphold the invisibility. 
Gain the effects of spider climb

Aspect of the Owl:
You can see in all directions around you simultaneously and you gain dark vision if you don't already have it.
Add 5 to Animal Handling, Insight, and Survival rolls as well as your normal bonuses. 

Aspect of the Crocodile:
Swim speed is equal to your walking speed +15. 
Add 15 to perception rolls while underwater, as well as your normal perception bonus.

Tranquilizing Strike

Once per long rest, when you make a ranged or melee attack you can choose to add a tranquilizer to the strike. The creature must make a constitution saving throw against your spell DC. On fail the creature becomes unconscious at the end of it's next turn and remains in this condition for 1 round +the difference between the amount rolled in the save and your spell save DC, or until it takes damage of any kind other than psychic. The creature can also make an intelligence saving throw to know if it has been tranquilized, before falling unconscious. 

Cobra Commander/ Mongoose Sidekick

Choose either 3 small venomous snakes or 1 mongoose to be your companion(s) From this point on. You cannot change your choice after it has been made.

Cobra Commander
3 Small venomous snakes are now your companions. These snakes act similar to familiars but have limited movement speed and can only perform 3 actions: attack, dash and hide. 
The Snakes do not have initiative, instead you can command all 3 (or less if you choose) to take actions as your bonus action. 
The Snakes:
3 HP, AC 15, 10 run and swim speed
STR 2 (-4) DEX 16 (+3) CON 11(0) INT 4 (-4) WIS 10 (0) CHA 4 (-4)
Actions:
Dash, Hide
Attack: Bite Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 3d4 piercing damage, and the target must make a Constitution saving throw(Ranger's DC), taking (5d4) poison damage on a failed save, or half as much damage on a successful one. 

You have a telepathic connection to the snakes up to 100 ft. If any of your snakes die, spend a total of 2 days per snake outside (does not need to be consecutive) to find and tame new snakes. 

Mongoose Sidekick
A mongoose is now your companion. The mongoose acts similarly to a familiar. The mongoose does not roll initiative, instead you can use your bonus action to command the mongoose to take actions. 
Mongoose:
10 HP, 15 AC, 35 Run speed
STR 8 (-1) DEX 16 (+2) CON 14(+2) INT 12 (+1) WIS 12 (+1) CHA 10 (0)
Actions: 
Attack: Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: (4d4 + 2) piercing damage.
Dash, Disengage, Dodge, Help, Hide, Improvise, Ready, Search, Use an Object

The mongoose has +5 to stealth checks. It is resistant to poison damage. The mongoose can sense the presence of reptiles, especially snakes, within 100 ft (beast or humanoid). You have a telepathic connection to the mongoose up to 200 ft.
If your mongoose dies, spend a total of 5 days outside (does not need to be consecutive) to find and tame a new one. 

Aspect of the Hydra

Once per long rest, apply 2 more bestial aspects of your choice for 10 minutes. When the effect ends retain 1 of any of the 3 active aspects until your next long rest.