Ok so, I personally would focus on 2 things when making vampires, tokens and aristocrats. Edgar Markov is broken because every time you play a vampire, you get a second one, this is incredibly easy to abuse by either making all your vampires stronger with lord effects or using the tokens for value, so why not do both?
Me and my friend both made versions of this deck before, mine was go wide aggro and his never attacked every but just won though aristocrat effects, both were very strong. Below are some key cards that can help this, broken down in terms of price. Some of them are better than others but I didn't rate them individually since it really depends how you want to take the deck. It's worth thinking about what your game plan is though. Edgar is amazing at spewing out tokens but what then? Do you use them to overun your opponents with buffs and aggro or do you use them for value by sacrificing them and pinging down your opponents over time, removing your crappy tokens so they lose their big boss creatures etc.
You probably shouldn't add every card listed here, so take these below as options to add. You don't want to go overboard on creatures (40 is too much IMO) because then you lack interaction with the board, but if you run too little you will not get any of the value off Edgar and soon get overrun yourself. I'd ideally have a core of 15 or so vampire that have really strong abilities, great value like Vampire Nighthawk or Captivating Vampire etc, then 15 or so vampires that either buff your other vampires, go on a theme you like (such as blood artist being aristocrats), or have some other purpose in the deck (crypt ghast for mana ramp, Bishop or rebirth for reanimation etc).
Super cheap cards to add + consider (>$1):
Etchings of the Chosen (you will be making tons of vampires, each vampire you have makes another one so a +1/+1 effect becomes worth double. Also because you have all these small vampire tokens, saccing them for value is great)
Falkenrath Noble (Solid vampire flier, effects like this and on Blood artist really add up across the course of a game, especially when you're the one sacrficing your tokens)
Voldaren Pariah (Sacrifice outlet for tokens and a devastating flip effect against certain decks)
Bishop of Rebirth (gets back all your cheap lord vampires)
Sangromancer (Amazing value)
Read the Bones (Solid Card Draw, the deck doesn't need much but 2-3 cards like this to refresh the hand help)
Champion of Dusk (You gain so much life that spending it is easy, and even if you didn't gain life it'd be worth including)
Victimize (Turn one of your meh tokens into 2 dead creature, great value)
Mind Stone (decent mana rock, you might want to add 2-3 more to the deck)
Cards worth including (<$1 >$3):
Commander's Sphere (See mind stone)
Mirror Entity (Late game you play this, dump mana into it and win)
Gifted Aetherborn (Just a solid vampire, worth including if you lack low costed vamps)
Radiant Destiny (see Etchings of the Chosen, but also you get The Cities blessing super easy, this costs 3 mana so by the time you play it you'll have at least 4 permanents, + 3 vampires to make 10 permanents off tokens as well).
Sanguine Bond (Life gain synergy + blood tribute combo)
Anowon, the Ruin Sage (Your opponents will hate you but it's worth it, stops them playing 1 dude on an empty board cos it'll die)
Cleansing Nova (Cheap boardwipe with modes, solid card)
Go for the Throat (On theme and strong cheap removal)
Terminate (See above)
Tragic Slip (See above but worth noting you can sac your own thing to get Morbid AND it gets around indestructible)
Viscera Seer (It's a vampire for 1 Black and a free sac outlet, what's not to like?)
More expensive but really solid stuff (<$3 >$10)
Vampire Nocturnus (surprise win by making all your vampires bigger and flappier)
Vanquisher's Banner (Makes all your vamps bigger and cycles though your deck)
Kalastria Highborn (If you go into the sacrifice theme this is great value)
Ashnod's Altar (Really strong card, sees tons of play in EDH, free sac outlet for mana is always useful)
Skullclamp (This card is literally broken, as in Magic R&D admitted it was changed last minute before it went to print and they didn't have enough time to test it and regret it being printed broken)
Cathars' Crusade (Since every vampire makes a vampire and they both trigger this, your guys will get out of hand fast)
High Market (Sac on a land, solid)
Crypt Ghast (Ok so yes it's not a vampire BUT it gives you crazy mana ramp)
Divine Visitation (Funny as hell if you can get it to stick)
Shared Animosity (Makes all your dudes swing for lethal easily and is cheap)
Necropotence (The card that literally broke magic for a year)
Vish Kal, Blood Arbiter (So big vampire, flying, lifelink AND a sac outlet AND removal? Seems good)
Torment of Hailfire // Exanguinate (Just wincons in Black)
Blasphemous Act (9/10 this will cost 1 Red to wipe the board)
Big Bucks stuff (<$10)
Coat of Arms (drop this and win unless other people are playing tribal)
Anointed Procession (doubles all your vampires and any other tokens you might make (see smothering tithe))
Exquisite Blood (You'll gain a billion life and wins the game on the spot with Sanguine Bond)
Elenda, the Dusk Rose (Amazing value vampire)
Sorin Markov (You know how EDH is a 40 life format? Let's make that 10 instead)
Smothering Tithe (New white staple for EDH, should be in every white deck that can run it)
