I'm more fond of Huntail, but Gorebyss has a charm of its own. I like that the Pokedex pulls no punches in stating that its vibrant pink coat are an effect stemming from Gorebyss's predatory, hematophagic nature. Subtly disturbing animals like these are fun, and I always appreciate obscure marine life. So... yeah, Gorebyss is cool.
Not one I think about too often, but I have to admit, I actually quite like the design concept of this one a lot, like how the Pokedex (and its typing) implies that it's actually the seaweed itself that's the ghost and that the anchor-ship's wheel stuff is just being possessed by it.
Yanmega is one of the better cross-gen evolutions that Gen IV gave us. Air Slash + Speed Boost was insanely powerful when I used it in Platinum once. Yanma, while cute, wasn't a good battler and I bet a lot of people in Gen II and III just caught one to complete the Dex.
My favorite Baby Pokemon. A cute Anubis pupper. The only problem I have with its design is that I have to constantly remind myself that the black teardrop-shaped things hanging from the sides of its head are not, in fact, its ears.
My favorite Johto Pokemon, I've liked Girafarig for quite some time. Probably ever since I've started playing Pokemon now that I think about it. It's weird design just clicks with me though I kinda prefer beta Girafarig to be honest.
I'm usually pretty heterodox in terms of Pokemon tastes, but I don't really see anything likable about Stantler. It's.. a plain Normal-type deer with a face only a mother could love and a subdued shishi-odoshi motif and that's it.