I don’t know how many people will be reading this, but I wrote it as if the whole world is watching. Recently I got the Pokemon Deluxe Essential Handbook. It has a few errors and omissions, and soon Sun and Moon will be released, but it’s still a great resource for any Pokemon fan. Having read the whole book, I can post a definitive list of my favorite and least favorite Pokemon. This is just my personal opinion, and if you don’t agree, that’s fine. We all have our own tastes, and it’s interesting to see what Pokemon other people like or dislike, as long as the conversation stays cordial. All of those can be found on Bulbapedia .
There are a lot of Pokemon I find cute (like Squirtle and Marill) and interesting (like Gastly, Rotom, and Frogadier), but these are my definite favorites.
- Arbok- It’s an intimidating creature and I’ve always been fascinated by cobras (although I like hyenas and lambs too and don’t care much about Mareep or Poochyena & Mightyena). I also liked the battle cry in the anime. “CHARRRR-BOKKA!”
- Charmeleon- It’s cool-looking and formidable, and I like the play on “chameleon”. It’s a shame that the anime’s main depiction of Charmeleon was a self-centered, hateful brat. However, there was one in the episode with the Crystal Onix.
- Croagunk- It’s cool looking with interesting abilities, and I loved Brock’s Croagunk. It was tough at some times and casual at others. “I’m just chillin’ with my cheeks puffing in and out!”
- Exeggutor- I never thought much of Exeggutor until recently. I saw some Pokemon Stadium videos by vussj vussj on YouTube, and they made such good use of Exeggutor that they made it seem like one of the most awesome Pokemon ever. I want one of my own now.
- Gligar and Gliscor- I like the bat-scorpion blend, and I also like how goofy Ash’s Gligar/Gliscor was. It was always a day late and a dollar short, but its heart was in the right place. There was also an episode of Pokemon Johto with a local crimefighter named Gligarman and his pet Gligar. He talked about his secret identity, but near the end, when he was his trouble, the townsfolk started rooting for him by his real name. He found they really cared for him and appreciated what he had done, which was cool.
- Infernape- I like Infernape for basically the same reasons I like Charmeleon. It looks awesome, it’s a tough fighter, and I like the play on “inferno”. This is one of my favorite monkey Pokemon. It’s loads better than the messes that are Ambipom, Simipour, Simisage, and Simisear. Incidentally, is it just me, or should Panpour and Simipour be named Pansoak and Simisoak instead?
- Jigglypuff- It’s cute and it has that lovely song as one of its attacks. I started liking it because of the anime, though after a while it got old.
- Kabutops- I never cared much about this Pokemon for some reason (perhaps because I didn’t care much for the anime episode that introduced me to it- which totally botched its strengths and weaknesses, by the way), but now I like it because of its similarity to Scyther. I also think the idea of it being a Rock-Water type is interesting (and yes, I know it’s not the only Pokemon with that type pairing).
- Krokorok-It’s a cool Pokemon, and I love Ash’s Krokorok/Krookodile. It was so powerful and looked so rad with its sunglasses, but it was distraught if it lost the sunglasses. I think there’s a little of Ash’s Krokorok in all of us.
- Mankey- This is my other favorite monkey Pokemon. The thing I like is that, unlike other monkey Pokemon, it’s not stylized. It has a simple appearance that makes you think that if pig monkeys did exist, this is what they’d look like. It’s interesting that I like the appearances of both Infernape and Mankey, and yet they look so different.
- Noibat and Noivern- It goes from being this cute bat creature to this awesome bat dragon creature. I also like how the bat Pokemon use sound waves like real bats. Swoobat looks pretty neat too.
- Psyduck- Psyduck looks so clueless, but it comes through when it’s the most needed. Also, since I’ve had headache troubles since childhood, I can identify with Psyduck.
- Raichu- This is probably my all-time favorite Pokemon. I just love everything about it. It’s a shame that it’s often thought of/dismissed as a rival for Ash’s Pikachu. Luckily there are a lot of other Raichu fans out there.
- Scyther- If Raichu is my favorite, then Scyther is a close second. It has one of the coolest and most intimidating designs in the whole series. I especially loved Tracy’s Scyther in the anime. It was tough, but showed a softer side to the smaller, weaker Pokemon, and it had great determination and loyalty. It’s great that a Pokemon got a backstory and character like that.
- Sewaddle, Swadloon, and Leavanny- It’s interesting that Sewaddle and its evolutions are Bug-Grass types (Once again, I know there are others). I like how Swadloon looks like it’s wrapped in a blanket, and it’s been pointed out that there’s symbolism in the fact that it evolves through friendship. Leavanny is one of my new favorites. People say Ash’s Leavanny sounds like someone’s drunk aunt, but I just think that’s part of its charm. I also like that Ash’s Leavanny is male, defying stereotypes and expectations.
- Shedinja- I just love that there’s a Pokemon based on a cast-off cicada shell. The first time I found a cicada husk it scared me, but now I just find them fascinating. I found a lot of YouTube videos talking about Shedinja, so I’m not the only one interested in it.
There are a lot of Pokemon I find ugly (like Pinsir and Steelix) or unimpressive (like Scizor, Tangrowth, and Gourgeist), but here are the ones I dislike the most.
- Delphox- I just don’t like it. For one thing, it tries too hard. “Ooh, look, it’s a witch! Whee!” For another thing, it looks like it has out-of-control ear hair. “Delphox, use Mystical Fire!” “What’d you say? No, I didn’t miss any coal fires.”
- Lickilicky- It’s ugly and unnecessary. Of all the unnecessary evolutions, this is my least favorite. They took something that was proven to be interesting in the anime and turned it into this monstrosity. Why, Pokemon designers, why!?
- Magearna- Just look at it. 
- Medicham- It’s ugly and also reminds me of people who brag about their achievements (Things like yoga are supposed to be done for self-improvement and spiritual growth, but some people just love to brag). I do think its mega-evolution is neat, though. By the way, does anyone else think Meditite looks like a Smurf?
- Mega Mewtwo Y- Why, indeed.
- Probopass- Poor Probopass gets no love, ending up on many worst Pokemon lists. It’s ugly and pointless, though I have to admit it is different, and the iron powder for a mustache reminds me of that toy where you use iron fillings and a magnetic wand to give a bald face hair. In that light maybe I dislike it less than I first thought.
- Slaking- This is probably my least favorite of all, and much of it is due to a recent video I watched. The player was trying to battle with a Slaking and half the time (maybe even two-thirds of the time) it had messages like “Slaking is slacking off” and “Slaking seems unable to use its power.” I can take an ugly Pokemon, but ugly and useless? Also, the fact that Slaking is considered a pseudo-legendary made me think, “Really? Well, that’s disappointing.” It’s like someone who churns out icky, yucky, nasty, stinky poetry being named Poet Laureate (which has happened, but I digress). Snorlax is lazy too, but it can be useful (The Pokemon Adventures manga had an issue showing its potential), and there is a certain charm to that sloth-bear face.  The cocoon Pokemon are considered useless, but they at least try. I’ll take a Combee or a Magikarp that’s eager to try over a pseudo-legendary that doesn’t care any day of the week. [Note: I recently found out it's not really a pseudo-legendary, it's just mistakenly believed to be one, so that's something of a relief]
- Timburr, Gurdurr, and Conkeldurr- Hey, ever wonder what it would be like to have Pokemon seemingly inspired by grotesque smirking juiceheads? No? Me neither.
Sun and Moon Update
- Decidueye- I really like the archer design, and its typing is interesting too.
- Litten/Torracat- You have this cute, roguish little kitten and this tiger-like and menacing, yet still playful-looking, big cat.
- Brionne- Isn’t she cute?
- Lycanroc Midnight Form- I have a sort of fascination with werewolves, and this one has a wicked awesome design.
- Wishiwashi- I find it cool that this little fish summons its friends to form a truly formidable opponent.
- Lurantis- I just like its design and coloring.
- Salandit- This is one of the more unique new Pokémon, with a special typing and a wicked Ability.
- Golisopod- It starts out as a wimpy little thing and then turns into a powerful monster.
- Alolan Persian- Cripes. Persian was turned into this!? I’d say something, but the Internet has done that for me.