A few critters to consider:

War Dog
Aggressive- Will engage anything owner advances
Defensive- Will engage anything that advances owner
Utility- Can carry a 'note' or small item
standard- don't like other dogs. When owner dies, dog barks in neighboring areas

War Wolf
A- Same as War Dog. Can be set after a target
D- Same as War Dog. Can be told to guard item/person.
U- Same as War dog. Tends it's own wounds.
S- When owner is bleeding, dead or alive, the War Wolf Licks it's owners wounds to tend them. In the event of death, the tending is followed by howling that will be heard a good distance.

Paguur
A- None
D- Distracts attackers leaving them unbalanced
U- carries notes or small items. Steals from target when ordered to.
S- Musses random bystanders hair occasionally. Great for parties.

Pole Cat
A- Same as War Dog. Special ability is a stunning spray attack
B- Same as A
U- Same as War Dog
S- can ruin a party

Warboar
Need I say more? Best to keep this one on a chain, especially when it co-berserks with you.

Rok
A- Same as War Dog.. aerial assaults
B- Same as A
U- Carries notes and small items long range. Can carry a dead owner to a pre-designated location
S- Has an ear-piercing shriek on occasion

Pard, Jaguar, Jungle Cat
Call it what you want.. we need one

Ferret
Gads, this one is gonna get that young barb in trouble.

And finally...
War Mammoth
A- Same as War Dog. Special attacks are many and painful.
B- Same as War Dog. Special attacks keep coming.
U- Ride-able. range weapons only from mount. Can carry one other besides owner. Not good messengers as they scare the public.
S- Rangers can train them like a horse. They can swim but that Gondola is iffy.