Meloetta is your favorite! Or at least I'm pretty sure. XD
Anyway, I wouldn't have expected Gengar or Darkrai to even be in this list, let alone in your top 10. It seems like everyone would put Charizard and Lucario on their list, but they are great Pokemon.
So, here we are. We're at #1 now, my favorite Pokemon ever. In order for a Pokemon to be here, I have to love its concept, appearance, battling skills, and anime appearances moreso than any other. Who's that Pokemon?
#1:
#1
Surprised by this? I'm sure some of you are, but this may be expected to others. Meloetta is my favorite Pokemon ever. I love everything about this Pokemon. None out of 717 others can even come close to topping Meloetta. Meloetta's backstory is that long ago, she sang and danced to bring joy to everyone's hearts. However, she lost the special melody along with some red shoes. That's quite a sad backstory. In addition, Meloetta has two forms: the Normal/Psychic singing Aria Form which puts Jigglypuff to shame and the Normal/Fighting dancing Pirouette Form which is an extremely fast physical attacker. In Aria Form, she's said to have inspired musicians into writing songs and has green Rapunzel hair longer than her own body. Pirouette Form comes with a beehive hairdo and tons of dancing. By using Relic Song, her signature move, Meloetta can transform between forms which resembles that of a magical girl and can even put foes to sleep if lucky. Speaking of which, Relic Song is the main reason why Meloetta's so great in battle, as she's able to dish out damage from both physical and special sides, and she's even got the movepool to take advantage of this. Those hair decorations are also extremely fitting for a music-themed Pokemon. The anime appearance arc starring Meloetta is one great arc showing of Meloetta in a load of charming musical glory. What else can I say? Delightful appearance, great battling skills, an inventive concept, and an enjoyable anime appearance are all the reasons why Meloetta is #1.