Rideable animals

while there is a wide variety of animals within the isles, a fair few of those are able to be ridden as mounts by various sentient species,

Epicyon:
giant wolves each larger than a horse "common" amongst the people of Anastria as the dense forests make it hard for hippogryphs or horses to navigate between villages and cities not to mention the fearsome teeth Epicyon possess.

Although it is common for entire packs to pair with a particular family or clan of Anastria, and forming a bond like that of Tevin warriors and their hippogryphs, most Epicyon fight alone and so it is rare, but not impossible for an Anastria native to earn the trust of one and so bond with them but that is not an easy trust to earn be warned.

Hippogryphs:
Half bird and half horse are the hippogryphs, common across the isles but humani have come the closest to mass taming them meaning most people of any means will at least know of someone who has a hippogryph as they are only slightly rarer than horses themselves amongst the populace, which has caused Hippogryph riders to be used to set up a sort of postal system across the empire. As for appearance, while most hippogryphs can be described as having the body and legs of a horse and the head of an eagle (plus wings sprouting from their shoulder blades) there are a few regional variants of note, for example the people of Tevin have a hippogryph resembling a pony and kite while on Attacks itself likely due to the high background radiant, a dove and rat hybrid hippogryphs has appeared and etched a niche out for itself.

Oberon Elks:
Part divine symbol, part pack beast, and part mount are the Oberon Elk, massive Elk with racks of antler that can stretch up to an impressive twelve feet, although only those owned by an elven lord or the centerpiece of a temple will be allowed to have antlers that long, these massive beasts are believed to be gifts from Oberon himself to serve the wood elves (although high elves, celestial elves, and night elves have all be seen to have their own breeding populations) as needed meaning that all wood elves who are likely to travel frequently or move heavy objects will own at least one.

Giant rats:
Originally the ancestors of these giant rats were normal sized rodents who came for the prehistoric dwarf's grain stores, however some mad man of a dwarf saw a use for them and began breeding them to be more friendly to dwarves, and perhaps more importantly, larger, and while it has taken thousands of years, the giant rats have been born, each the size of an average sized boar, they are perfect for whenever a dwarf, no matter the variant needs a ride somewhere as their natural instincts make them ideal for navigating the cramped often pitch black confines of their underground home.