10-Sharpedo
This is kind of a surprising pick, but honestly I just love sharks. Sharpedo is just an awesome Pokemon. Also Sharpedo Jet Skis!!!!
9-Alola Ninetales
I always 'liked' Ninetales but with this brand new form I now 'love' Ninetales...It's like this is what Ninetales was meant to be, it always felt like such a mystical pokemon as it was but as an Ice/Fairy it just takes a whole new level...It's so beautiful and majestic
8-Vikavolt
It's pretty surprising to me that an electric type is in my Top ten favourites, but Vikavolt is a definite outlier. (I don't dislike Electric but I almost never use them in game) Competitively Vikavolt is...mediocre, but I don't care it's such an awesome pokemon! It's design is great and it's typing paired with it's ability is great! I just love it!
7-Heracross
Heracross served as a solid regular on many of my teams throughout Gens II and III and even a few playthroughs in Gen IV, I took the time running around for days and days slathering trees with honey to get Heracross in Sinnoh. This bug is a beast!
6-Haxorus
People can say all the bad things about Unova they want, but that region gave us this monster!! X and Y made dragon mono-types extremely easy as Axew is the first possible dragon type you can acquire in the game and Haxorus was easily the mvp in that game as it was the best Pokemon to use against Fairy types as it can learn both Poison Jab and Earthquake to deal with all Fairy types. Also I WANT MY DRAGON/STEEL MEGA HAXORUS GAMEFREAK!!!
5-Scizor
Actually having a pokemon buddy back in the day while I had Crystal and he had Silver. I managed to get myself a Scizor (unfortunately only for post-game since I wasn't aware of Theif and Hold Items) but Scizor was an instant mainstay on my team. It has an amazing design and a great typing and is a competitive monster! It's mega form is one of my go-tos in OU play and one of my favourite Megas. Was also the second pokemon I naturally raised to level 100 in a pokemon game.
4-Sableye
Unfortunately I played Ruby back in the day...I thought Sableye was a pretty cool pokemon back then but I was never able to use it. But then X and Y happened and was able to use it finally, I loved using this little goblin as well as it's really neat animations, the swaying hips, the twitching and it's nasty ass grin. Then I had my first taste of competitive battling. Prankster Sableye is a monster and being able to shut down entire teams with nothing but this little purple goblin with a **** eating grin on it's face as it keeps taunting all the T-tars and Garchomps and chucking Will-o-Wisps.
3-Rayquaza
By far my favourite Legendary Pokemon! Easily has my favourite Mega form which has, IMO, one of the strongest designs out of all of the pokemon. The Delta Episode in ORAS has really boosted how much I love this pokemon! Also there's no other opportunity in any pokemon game to ride a mythical dragon into space and fight aliens!! Also Rayquaza was a pretty cool boss in Brawl!
2-Salamence
I remember playing through Hoenn back in the day and being intruiged by Meteor Falls, and being anxious to get Waterfall so that I could explore it...When I was able to access the caverns I explored the crap out of the cave and was somewhat disappointed other than finding Iron Tail and Dragon Claw. After finding Dragon Claw, I knew there wasn't much else this cave had to offer so I just decided to start grinding at the back of the room...until I met with an angry miniature blue yoshi and I knew I just had to have it on my team!!! I also love how Salamence is a embodiment of achieving your dreams!
1-Sneasel
Sneasel is the Pikachu to my Ash! Every single time I play Pokemon Crystal I HAVE to have a Sneasel. I still remember finding one in Ice Path! At that time I never knew about physical or special but Sneasel was a pokemon that ran through most of the Elite Four other than Bruno's fighting types and Lance's Gyarados! Not to mention how I had a bit of rivalry with one of my pokemon buddies back in the day and Sneasel one shot his Charizard with Surf! Sneasel was also the first pokemon I ever raised up to level 100 (legitimately without the use of cheats or glitches)!
For those wondering, yes I do still like Weavile...however I only like Weavile as much because of Sneasel. Weavile would be like Number 1.5 but nostalgia just wins out in this regard.
Honourable Mentions:
Cacturne, Banette, Crawdaunt, Lycanroc (Midday), Gyarados, Metagross, Toucannon, Typhlosion, Torterra, Mimikyu, Kommo-o, Tyrantiar, Tyrantum, Sceptile, Relicanth, Nidoking, Alakazam, Hydreigon, Staraptor, Honchkrow, Noivern, Flygon, Mismagius, Umbreon