I know dogs are in the works already, and I had an idea for how they'd breed. Once tamed they start out looking fairly wild, close to the wolf. Hearthlings can breed them for certain stats and this eventually gives newborn puppies a different model. Quality determines how well they do the thing they're bred for. Villages could specialize in one or a few dog breeds, then trade for the others. Dogs could also be bred back to original or changed into another breed if their stats change enough.
Original - Well rounded dog. Jack of all trades, master of none.
Strength - Leonberger. Could pull a small cart alongside their master if such a thing were added.
Speed - Greyhound. Can keep up with a horse at third speed.
Scent - German Shepard. Tracks blood trails or criminal scents.
Big game hunting - Great Dane. Strong against large animals such as bears, moose, etc.
Small game hunting - Dachshund. Strong against small animals like badgers, foxes, etc. Picks up rabbits, squirrels, etc.
Water hunting - Poodle. Originally bred as a water-retriever. Strong against beavers, otters, etc.
Bird hunting - German Pointer. Strong against swans. Picks up smaller birds like quails, chickens, etc.
Herding - Border Collie. Increases speed of leashed animals, helping them keep up with hearthlings. Assists taming.
I get that this would be a lot of work to add, I'm certainly not expecting it to all be included the second dogs come out. It's just a suggestion for a long term project.