13.
This is a starter line that has an appealing design at all 3 stages of it's evolution. Snivy is sassy. It's got it's big, Cyrano Debergerac-like nose in the air, but it's still looks chill and inviting too with that slight impudent smile. You can see it thinking, "Yeah, you know you want to be a cool kid and pick me, right?" All that attitude packed in this pint-sized starter Pokemon is hard to resist.
The one we're at now Servine becomes more graceful than snivy with the more pronounced s-curve and ivy flowering around it body. It's a very nice-looking Pokemon. It also still has some personality, it's matured from snivy and it's facial expression is subtler than before, but there's still a little sphinx-like smile on it's face.
My personal favorite Serperior is very tall, striking and less approachable. They're going for a theme of French royalty with the golden fleur-des-lis pattern for scales and high collar, and this Pokemon looks like it just slithered off of his throne, as it shoots a searing gaze at it's inferior.