Just my list, feel free to name yours.
1. Reign Of Blood - http://reignofblood.net/
Reign Of Blood is a free online Vampire Roleplaying Game. The player takes the role of a Vampire. To survive, he must train and fight others in order to survive, and become the most powerful and the richest vampire.
Here you must keep your wits about you and train hard, for the Dead City is a deadly place, even for those Unliving. Grow stronger, swifter, and tougher, or be swallowed by the legions of the mighty. The Battle arena is where you go to do all of your killing so you may rank up. There are a few diffrent ways to search through players. When you find a player you want to attack then simply click the [Attack] button or go to their profile then click the attack link.
2. City of Eternals - http://www.cityofeternals.com/
City of Eternals is set in the city called "New Valencia", where you complete missions and adventure to become the ultimate vampire. You can achieve that in many ways, including: defeating monsters and other vampires in combat, harvesting raw materials and crafting precious items, and completing mission adventures in New Valencia. The more you perform these activities, the more powerful your vampire becomes. You can also customize your clothing and home, and meet fellow City of Eternal players from around the world. You can even create your own vampire House by turning your friends into Minions who do your bidding!
3. Rogue Vampires - http://www.roguevampires.net/
The Rogue Vampires is a browser game where you play a vampire set in a fantasy world. Rogue Vampires is where to succeed you're required to train hard and convert as many humans as you can. You can either spend all day in the gym training to beat your enemies, either inside or outside the Battle Ladder, or join a Covenant and work as a team destroying others to be a part of the best around. Be a merciless hitman, compete for #1 in the hall of fame, learn the market to earn money. Start a deadly Vampire House and spread fear all around you or simply just train so that you one day can be the most powerful Vampire out there.