I love vampires. I'm trying to make a Mardu Vampires, I know a lot of vampires do +1/+1 but I'd like to do Mardu control. Here's what I got, open to opinions on how to get this stronger. My Commander is Mathas, Fiend Seeker not sure why it can't put it in my deck list.
I haven't played vampires myself, so I can't help much with the creatures, but most seem OK here. I'm a fan of Legion's Landing, because that is a creature and essentially ramp for 1 mana, also it's a vampire.
However, I'd cut almost all of the instants and sorceries you play. Keep Crackling Doom, Fatal Push, Go for the Throat, Lightning Bolt, Swords to Plowshares, Teferi's Protection and Terminate. Cut the rest. They are either too expensive for what they do or they are plain inefficient in multiplayer like 1 for 1 discard or targeted land destruction. Spells I would add are Abrade, a super versatile and efficient removal spell. Wear//Tear, Toxic Deluge, Fire Covenant, Blasphemous Act, Jeska's Will, maybe New Blood and Boros Charm. Vandalblast is another great card for red. And if you like the Fireball effects (which are generally too weak in EDH usually), I can recommend Shatterskull Smashing. This is a Fireball which doesn't take up a spell slot because you usually play it as the land, which makes it a great card. Cathars' Crusade is a great finisher if you're playing Edgar. Gets out of hand really fast.
You should also work on your land base, remove the taplands and replace them with lands which enter untapped. It makes a huge difference, taplands essentially set your back a turn.
I'm working on getting lands that don't enter tapped. I know the flip lands like Blightstep Pathway, Shock Lands, etc. is where I want to go. I'm not forking out money for dual lands though. Even Badlands at $300 is too much for me, I can get an entire deck in standard at that point. I'm playing Mathas, not sure why it wasn't on there but I fixed it.