Spirit of the Elements

Flamebonder

Starting at 3rd level, you can now tap into spirit magic from the Elemental Plane of Fire. Your wildbond's size increases to Small and it gains resistance to fire damage. When it hits with an attack, it can choose to deal fire damage instead of the normal damage type for its attack.
  Additionally, when you or your wildbond hit with a melee attack, the attacker takes an additional 1d4 fire damage. If you or your wildbond is grappled by a creature, that creature takes 1d4 fire damage at the start of each of its turns until it releases its hold.
  Both damages increase to 2d4 when you reach 10th level.
 

Landbonder

At level 6, you can now tap into spirit magic from the Elemental Plane of Earth. Your wildbond grows rocky spikes all over its body, gaining a +2 bonus to its AC.
  Additionally, you can cast pass without trace once with this trait, requiring no material components, and you regain the ability to cast it this way when you finish a long rest.
 

Seabonder

At 10th level, you learn to tap into spirit magic from the Elemental Plane of Water. Your wildbond grows fins and gills. It gains a swimming speed equal to its movement speed, and it can now breathe water and air. If it already has a swimming speed, its swimming speed instead doubles. Opportunity attacks made against your wildbond are now made with disadvantage.
  Additionally, you can cast control water once with this trait, requiring no material components, and you regain the ability to cast it this way when you finish a long rest.
 

Airbonder

At level 14, you have figured out how to tap into spirit magic from the elusive Elemental Plane of Air. Your wildbond grows wings, and it gains a flying speed equal to its movement speed. If it already has a flying speed, its flying speed instead doubles. If your wildbond flies at least 20 feet on its turn, it gains advantage on its next attack.
  Additionally, you can cast fly as a 3rd-level spell once with this trait, requiring no material components, and you regain the ability to cast it this way when you finish a long rest.