I had a lot of favorites and obvious 2 of them are Garchomp and Lucario. Although my love for Garchomp has kinda went down over the past few years.
Other than those two There are a few more.
Staraptor - I love bird type pokemon. I always have and before Braviary came along, Staraptor was probably my favorite.
Empoleon - I fell in love with Piplup and Empoleon, especially Empoleon. I love penguins to death. It is one of my favorite pokemon. I would love to have a life sized Empoleon Plushi.
Luxray - I didn't like Luxray for a while. When Pyroar came out, I kinda started loving it because they reminded me of one another and it would be fun to have a double battle using those two in real life.
Buizel - I love this pokemon. I love the orange color and at the time it was really unique, although until recently, I didn't realize it was a weasel and not a otter. But I still love it. I am not a fan of Floatzel's design.
Skuntank - Yeah I know, it is a skunk, but it is one of the most unique pokemon in the game. And it just loots amazing.
Hippowdon - You can probably tell by now that I love animal based pokemon. Especially if they are quadrupeds.
Abomasnow/Weavile - Honestly, I didn't really start liking this pokemon till the XY games. However, along side Flying, Ice is probably my most favorite skill. I love ice types and I wish there was more.
Electivire - Probably the better design of most of the evo pokemon of older pokemon.
Togekiss - I didn't like this pokemon much until it gained Fairy Typeing and kept flying.
Glaceon/Leafeon - Eeveelutions, need I say more?
Gallade - I didn't like this pokemon until it got its Megalution. I loved how it got a cape and I have been a fan of the Ralts line.... and not not for the reason most love Gardevoir. I am not like that.
Mamoswine - I have always loved elephant like pokemon, and although this one is a boar, I just love its Ice type. It has such a basic design, but I am fine with that. I really wish Donphan had gotten an evolution like Mamoswine, but with rollout.