All female:
Wolf: I have heard and read that they mate for life. Of course I am not sure I can domesticate a female wolf even if she were a cub but eh, let's dream a bit. The grayish fur with white, black, white, and brown details. The fluffy yet earthy texture is also very appealing.
Doberman, Rottweiler, and I think Pitbull?: I have a thing for big, strong females. It awakes some sort of primal desire. Imagining myself mating with one makes me think I have shown being a deserving mate. Plus, the canine bond is impossible to ignore!
Mares: They are strong, majestic, beautiful, loyal, and noble. Had met many countryside girls saying that mares even get jealous when someone tends them "too much". According to these girls, a mare feel like that guy is hers and hers only. Anyone that has a mare please feel free to to tell me if this is true or false. However, their physique alone and that they also have unique personalities is arousing!
Lionesses, Leopards/Snow leopards: if you have seen a big feline stretch in front of you you can see those strong muscles showing through their bodies. Big felines look like hypercars, luxurious, powerful, and aggressive...again. i have a HUGE power fantasy and being able to tame a big kitty and make her mine...a man can dream...
Hyena: I have a thing for musk, plus I have seen a video of a male hyena being a total pup. However, females are more dominant, they are also pretty smart animals. Also, the thought of them having an external pussy is exotic and fun to imagine. Sticking my cock in her while I am MARKED by her smell...
Dolphin: Heard they can develop feelings for a human. I don't know how I could realistically make a female dolphin fall in love for me and I am aware having an enclosure for her would be EXPENSIVE. But if I could, I'd really love having such a beautiful, smart creature with a libido as high as mine.
Sized up bat, owl, crow, and eagle: They are also very beautiful on their own. Bats are adorable from my perspective and I heard they are tameable. Crows are also pretty smart too. Avians are just so pretty but their size doesn't help.
Bear: if she didn't tear me apart or squeezed me like a tube of toothpaste while mating, that'd be a very hot partner. Also imagine the status of walking your bear pet!
I think I have more but those are all