Dungeon Beagle- Small but very loud hunting hound. Can cast knock by howling and barking for an entire dungeon turn (about 10 minutes). Impossible to cage and very difficult to train, but respond well to treats and ear scratches. Breeders are rare and specialized.
Fencing Hound- One of the Sword-Wizards most curious inventions in the recent years. Can wield a variety of blades effectively using only it's teeth. Independent and protective. Mercenary companies will sometimes "lend" out their trained Fencing Hounds to adventuring groups for a slightly cheaper rate than a man-at-arms. While the mercenary hounds are quite capable fighters, their lack of hands and bipedal legs can come at a disadvantage in the strange environments that dungeoneers often find themselves in.
Wraith Boxer- Large white dogs with a curious mutation: each one is deaf, and they can hurt ghosts. Breeders of Wraith Boxers tend to have a regional variation of hand-signed commands that they use to train the playful and energetic dogs. They are fantastic ghost-hunters and their immunity to a banshee's killing screech has made them popular companions for those looking to scavenge the places where those haunts may lurk. Some rare and expensive cross-breeds can smell magic auras or demons as well.
Samson's Mastiff- Look like a 200 pound mop with legs. Blessed with impossible strength and youth as long as their hair is uncut and they don't come into physical contact with the dead. Also possess a strange wisdom regarding battle-tactics, riddles, and chess. Several of the generals during the Age of Swords were in fact armored mastiffs. Incredibly rare and practically sentient. Many societies would equate forced bondage of a Samson's Mastiff to slavery.
|Like this handsome boy but with dreadlocks|
Dungeon Beagles - I enjoy giving players tools with drawbacks. A repeatable knock effect is pretty powerful but being super noisy seems like an appropriate limiter- though it would be hilarious if some players could figure out how to use this to break into a mansion or something. Based off my own beagle, who continuously figures out inexplicable ways to escape any enclosure.
Fencing Hound - Sif doggos. I like giving granular options for hirelings. Fencing Hounds would be somewhere on the price scale between "random lamp-holder hobo" and "semi-capable man-at-arms" and also give some interesting flavor to the world.
Wraith Boxer - Fairly straightforward but specific skill set. If a location has a banshee problem then maybe get a few of these to help. Their teeth should be able to effect ghost-type-things just fine.
Samson's Mastiff - Haven't gotten to play wargroove yet but I like the dog general. Heavily based off ArnoldK's Brynth Hounds and the biblical Nazarite. Maybe it's a surprise boss, or a Really Good Dog with a Strength score of 20 as long as it meets the criteria mentioned. The "can't touch dead" restriction should probably only extend to sentient humanoids and undead.
See Dans excellent list at Throne of Salt for even more good dogs.