Visit any magic academy, and you'll find that one of the most commonly talked about subjects is sapient and non-sapient animals which are capable of using magic, either for hunting, defense, or other means.

Jakobeast

Height: 2.5 meters
weight: 1000kg
Habitat: Arctic tundra
Uses: Livestock and fighting mounts
These large beasts are capable of using a telekinetic push, a large herd can create enough force to flatten entire forests. Despite their frightening appearance, they are actually herbivores.

Canines
Maalraas (Canis Nox Venator)

Height: 1 meter
weight: 35kg
Habitat: Forests
Uses: Guard Beasts
Native to most forests of the northern continent, these unsightly canines use cloaking magic, making them virtually invisible to aid in hunting, this ability has made them useful as guard beasts. Their personality is likened to that of a boxer dog, loyal, friendly and faithful to their masters, but distrusting of strangers.

Vornskr (Canis Praecantatio Venator)

Height: 0.8 meters
weight; 30kg
Habitat: Forests
Uses: Guard Dogs
Native to the forests of the Griffin Kingdoms (Hence the unusual name) these canines have the ability to detect magic users, using it to detect a small type of lizard, known as a Ysalamiri. this hunting method led to these lizards using magic to create a void, inside which nothing else can use magic. Due to their abilities, Vornskr are used as guard dogs, it has even been discovered that cutting off their venomous barb-tipped tails has a similar effect to castrating other species of dogs.

Hellhound (Canis Infernum)

Height: 1.5 meters
Weight: 50kg
Habitat: Tartarus and The Pit
Uses: Infernal sapient guard beasts from the depths of hell!
These beasts are highly intelligent, to the point of sapience, and are used to guard the high profile prisoners of the Pit and Tartarus. They use their fear based magic to keep the prisoners in line, they are also master trackers, with a large variety of tracking and locating spells. Their paws constantly emanate an aura of blue flames.

Felines
Displacer Beast (Cursus Velox Felis)

Height: 1 meter (at the shoulder)
Weight: 40 kilograms
Habitat: Forests/Jungles
uses: N/A
Native to the Forests and Jungles of Hordika Valley in Sauria. These arboreal felines have the ability to quick travel, that is to teleport to a location in their line of sight, allowing them to swiftly move from tree-to-tree.

Other
Boggart
Height: N/A
Weight: N/A
Habitat: forests
Not much is known about this creatures, only that they can transform into other lifeforms

Invertebrates
Psionic Beatles

Length: 1-2 feet
Weight: 20kg
Habitat: Forests and Jungles
These beetle-like, semi-sapient invertebrates have the ability to control a target's brain and nervous system, though they have to be in physical contact with the target.

3803974 interesting.

3804335 They're from the Star Wars expanded universe

3804369 I can tell!

3804397
I've added a few more, think you can think of some more for me

3805081 HAHAHA! of course I can!

3805304 if you would be so kind, please?

it has to provide an active role in hunting or defence (venoms and poisons don't count)

3805315 *begins going through Known World posts*

I have a number of hellhounds and other beasts....

I might have a few... They're all under the over-arching species of F.O.E(Formido Oppugnatura Exsequens) but each have different statistics.

The example of the easiest one is the Card Soldier found in mysterious forests. Armed with a scepter it's possible for it to rapidly deal damage to unprepared foes. F.O.Es are extremely dangerous and in some cases look human but there is always one important thing to remember. They are not sapient. Their mannerisms allow them to be hunters but in some cases will open themselves up to being attacked in return. In most cases, should you ever encounter one, run for your life. Run fast because all of them are capable of using magic to fight as well and you never know which spell each will use until they finally fire it off at you for a very painful moment.

More details about them provided here: http://megamitensei.wikia.com/wiki/F.O.E

Well I do have a suggestion for magical beings... and really my F.O.E. one wasn't that good. I do have a different one that is a bit better.

Shadows.

These aren't the shadows that are cast by light. Rather these Shadows are remnants of the subconsciousness' of now deceased people/ponies/whatever you happen to be. Anything that is capable of intelligent being has one. I suppose the easiest way to describe it would be this. All things have a front and a back. If the Persona is what you want others to see of you, then the Shadow is what you want to keep hidden. Thus a Shadow of a living person, when emerged, is a lot more dangerous than one of a deceased person. Shadow is really an overarching term as there are many varying kinds of them. Each have different weaknesses and resistances and even extremely variant appearances. Should you encounter the Shadow of a deceased person, you can probably take it... If it's of one still alive... run for your life.