Bear- allow to harvest specific recourses, I'm tired of berries
Chicken-Warn you for weather changes
Cow-keep the same
Bull-boost weight, needs a carriage saddle too
Elephant- U know how Persians had platforms on their elephants? Would be cool to see that here
Horse-Make it faster, make it inflict damage when going trough an enemy, allow some special attacks with the sword from it's back.
Lion-king of the jungle... give it a roar that makes the wild animals around come on your side for some time (give this ability a big cooldown)
Seagull-Notices if someone is nearby and warns you (like parasaur in ark)
Vulture - If someone/something is low on health, shows you where he/it is.
Wolf- Pack buff