I have several villains in my world that you may be interested in. My campaign has been going for almost a year now, and most of the party has reached 15th level. I think the descriptions will be more useful than the stat blocks, so that's what I've included.
Thanatos: A wyrmling red dragon wizard. He's part of a lich's magical experimentation. He's extremely smart (Int 22), and uses his magic to cover his weaknesses and augment his strengths. He has an annoying habit of retreating when he's losing and coming back better prepared for the next meeting.
Rake: Honorable, psychotic ranger. He's a noble, and extremely rich. He was bored with the standard trophy hunting, and started hunting sentient humanoids. Groups of harvesters kidnap people for him and bring them to his island. He treats them to a nice dinner and conversation, then hunts them the next day. He has a 10 year old child who is the only true joy in his life since his wife disappeared.
Dethel: A shrewd, selfish, power hungry eighteen year old, he was always jealous of his older brother who would assume the throne one day. He struck a deal with a vampire that helped him assume the throne. He arranged to have his father and uncle captured and turned into vampires under his control. Later, he let his brother rule the country for one day, then wrested power from him, uncovering his illegitimate heritage.
Sky: A mature adult blue dragon who exacts tribute from the desert city of Ariad and anyone who comes by her oasis. She has been doing this for the past 200 years, since she was a wyrmling. Because of this, is interested less in the intrinsic monetary value of things and more in unique magic items and things of beauty, like sapphires. Those who speak with her must show her the utmost respect or she kills their camels, takes their water, and chases them into the desert with her dragonfear and leaves them to die.
I hope this helps. I have a few others I could describe for you if you're interested.