Sylveon is even more hideous. Since I consider it hideous as my personal opinion, please don't remark by saying it is attractive, or any form of it, since that would be your personal opinion and would get us nowhere.
Garbodor rocks because of the impact it can have on the environment. Now, I know what you're thinking: How can it have a positive effect on the environment? Well, people hate it. They really, really hate it. They hate it and Trubbish so much that they'll do whatever is necessary to prevent it from existing or being empowered. Therefore, they won't litter, and power plants and the like will be more careful with industrial waste. People will be more eco-conscious for the most part.
Sylveon… If you really are going to reject design as a reason to like it, then I'm at a bit of a loss as of what to say beyond "first Fairy-type Pokémon" because we really don't know much about Sylveon. But since we don't know enough about Sylveon to pass complete judgment, you're being thoroughly unfair saying it's your least favorite Pokémon and I don't feel like I have to justify anything to you. But it really is a remarkably cute Pokémon. It has a strikingly beautiful color scheme, a nice, slender physique fitting of a Fairy-type Eeveelution, and its fangs give it a bit of an edgy side, much like fairies in real life… Err, in folklore.
It's the only Pokémon to have proper gender-based evolution. Combee has no male evolution, Kirlia has no female-only evolution and Snorunt has no male-only evolution.
F***ING MASQUERAIN BEING ANOTHER GOD-D*** BUG/FLYING MOTH EVOLVING FROM AN AWESOME BUG/WATER COMBO.