This is my standard vampire aggro deck. It's quite aggressive and tops out at 4-mana threats with minimal disruption maindeck. I've had a lot of success with it at my LGS so I thought I would write down my philosophy.
-Card Breakdown-
The 4-ofs:
Adanto Vanguard is one of the strongest 2-drops in standard right now. The reason its under the radar is because it doesn't look that good. It looks like a 1/1 for 2 with an expensive invulnerability clause. In fact, it is almost always a 3/1 for 2 that cannot be stopped. Try and find a 2-drop that trades with it, you won't find one. Moment of Craving is very good against it, but that is still an even trade on mana. This deck has numerous small life-gain effects that allow you to be very aggressive - I almost always pay the 4 life to keep him around.
Call to the Feast is another card that doesn't read that well, but is amazing to play. A 4 mana 3/3 would need some good abilities to see play, but the fact that you get the power and toughness spread over 3 bodies and each one has lifelink means you have a lot of good attacking and blocking options after playing this card. Any anthem effect like Radiant Destiny or Legion Lieutenant really cranks up the power of 3 dorks. I started playing two, then moved to three, and lately I've been playing the full four.
Dusk Legion Zealot is an innocuous fellow. He is a 1/1 for 2 and doesn't have any lifelink or deathtouch. Why run this over Gifted Aetherborn? The cantrip is huge. Aggro decks usually sputter and run out of gas at some point and this guy drawing a card is a big deal for the deck. He also feels terrible to kill for the opponent with spot removal, though if you have other vampire synergy cards, they are sometimes forced to. Therefore this card nearly always represents a small amount of card advantage by giving you a replacement card immediately and then doing something in the game (attacking for a small amount, blocking, or getting pumped by effects). Like Adanto Vanguard, the life loss is usually not a big deal.
Legion Lieutenant is an all-star lord. Look at Lord of Atlantis, one of the original lords of the game and still one of the best merfolk lords. The two casting-cost is what makes this an amazing card. Dropping this early acts like a lightning rod for removal, dropping it later when they are tapped out represents an anthem effect. He can be tricky to cast and is one of the reasons for running 3 Unclaimed Territory. I do like cutting him against approach decks or other decks sporting tons of wraths. If you can't count on your army sticking around, and you need sideboard options, this is the card I cut.
Skymarcher Aspirant is a great start for this deck. While it does trade with a lot of little opposing creatures early, it represents some fast damage and is almost always tempo-positive (they spend more mana to kill him than you did to play him, plus he probably did some damage). Ascend is very real for this deck and I've gotten the City's Blessing as early as turn 4, by playing a Call to the Feast. Once you ascend this guy, he might as well be unblockable.
3-ofs:
Legion's Landing
is an amazing magic card and part of the reason I feel confident running only 23 lands. This can be a totally acceptable turn 1 play or a great pre-combat trick to hit ascend or ensure that you will immediately flip into the land. The land is a great deal of inevitability against decks like Approach or control strategies that try to grind you out of threats. I don't run 4 because it is legendary and multiples can be awkward.
Radiant Destiny is a huge boon for all the weenies in this deck. A lot of the creatures go from 1/1 to 2/2 which is doubling their efficacy. Even going from a 2/2 to a 3/3 represents a spike in power. The ascend ability is icing on the cake which lets this deck really pressure other decks looking to race by presenting all your guys as both attackers and defenders. Three has been nice because while multiples aren't bad, they do taper off. Still it's one of the better turn 3 plays if we don't have one of our other 3-drops.
Sanctum Seeker is a boss. The card reminds me of Hellrider which was a dominant aggressive curve-topper in its day. This card can come down turn five after a call to the feast and immediately dome them for 3-4 damage and gain back some life. He makes racing impossible if he sticks around. The 4-toughness means he dodges a lot of the cheaper removal cards and they will usually need to spend 3-4 mana to take care of him (outside of Fatal Push w/ revolt!). I typically side this card out because I don't want anyone to have great targets for their removal and because a lot of my sideboard cards cost 3 or 4 mana. I've gone up to 3 of these maindeck because they are usually amazing game 1 and multiples are not redundant!
2-ofs:
Fatal Push needs no introduction. While there aren't many ways to trigger revolt in this deck, you have a ton of little guys dying all the time. Push is almost always tempo-positive by killing something that cost more than 1 mana which is perfect for this style deck. They get sided out when the opponent is on bigger creatures, but having them game one is great to keep momentum. You never want to draw very much removal, which is why there are only two.
Mavren Fein, Dusk Apostle provides a lot of virtual card advantage because you can often get a token the turn you play her. A 3 mana 3/3 is worth looking at in any color, but this one can potentially provide continuous advantage! If all you do is get two tokens and eat a removal spell, you got a "free" Queen's Commission worth of value out of your 3 mana. That is a great value for this deck and you'd love to play her on turn 3 every game but she is a legendary creature, hence two copies.
Yahenni, Undying Partisan is really a wildcard for this deck and he does something unique that the rest of the card pool for vampires doesn't offer - haste. Yahenni can screw up combat math for an opponent that taps out and help you push a lot more damage than you look like you are capable of. If you can just force bloodbaths and trades here and there then he starts getting bigger which is when the value starts getting nutty. Remember how a 3-mana 3/3 is a good deal from Mavren? Yahenni has similar potential to grow plus he has haste. I'm usually very likely to sac a guy to keep Yahenni around so I don't play him naked on an empty board very often. He gives you one of your few ways to trigger revolt for Fatal Push. Like Mavren, as a legendary at a relatively high mana cost, I've liked playing 2 copies to avoid having too many of them.
1-ofs:
Forerunner of the Legion is a funny little card. I used to run more with a singleton Vona, but I am down to a single copy. There aren't many silver-bullet vampire cards to search for, so what is up with this guy? Well, his ability is super relevant with all the token generation. Curving this turn 3 into a Call to the Feast turn 4 (with a pocketed Sanctum Seeker for turn 5? :)) is really strong. Sometimes he creates problems when you really need to hit a 4th land and this is your only reasonable play, so I have declined to search with him. Giving the +1/+1 bonus to Mavren lets you get even more value off her triggers and it's also great on a Legion Lieutenant to force a trade and push more damage through. Naturally it's also not bad on a lifelinking vampire. I would run more, but I haven't been happy with multiples and there isn't any room! Fun card and usually surprises opponents. Great topdeck.
Thopter Arrest is a really strong removal spell that I was ignoring for a while. It's only 3 mana and it stops every big problem card in the format. It cleanly deals with Hazoret, The Scarab God, Rekindling Phoenix, and on and on. This deck really doesn't want to draw too much removal during game 1 so there is only 1 copy. I maybe should replace one of the Ixalan's Bindings with another Thopter Arrest for curve considerations, but I really love getting people with the Binding on cards they run multiples of. I'm rarely unhappy to draw this singleton and it has a use in almost every match-up.
-Summary-
This deck has the ability to rebuild after wraths and doesn't have many great targets for expensive removal spells like Vraska's Contempt. Adanto Vanguard and Yahenni, Undying Partisan give the deck a lot of play against typical wrath effects (but be careful around Settle the Wreckage!). The lowly Dusk Legion Zealot gives a limited amount of card flow, but is cheap enough to really help dig for the last few cards. Call to the Feast is a really strong spell in this deck with Radiant Destiny and Legion Lieutenant. Even outside of the permanent buffs, you have Sanctum Seeker and Shefet Dunes synergy which tends to make the tokens much more valuable. Call to the Feast also gives the deck a lot of reach by helping to hit ascend with Skymarcher Aspirant for a flying threat as well as the 1-of Twilight Prophet which is an amazing final threat to play.
-Sideboarding-
The sideboard is tuned for my small LGS's meta which revolves around a lot of mid-range and control decks. I tpyically side in a LOT of discard when I'm on the draw against a control deck that has sweepers. Sweepers are the best cards against this deck so having 4x Duress gives you a lot of options to sculpt your lines around what they are doing. Some of my typical set-ups are:
VS. Approach
Out: Legion Lieutenant x4, Fatal Push x2, Thopter Arrest x1, and Sanctum Seeker x1
In: Duress x4, Gideon of the Trials x1, Ixalan's Binding x3
My philosophy is that you want a lot of answers to their spells. Sometimes I bring in the Arterial Flow instead of a Yahenni or a Mavren as well. The lords are weaker here because there are so many sweepers you can't count on them living long enough to push damage. They are also the most difficult to cast creatures on turn 2 and we are adding some slower removal. I prioritize hitting Search for Azcanta with Ixalan's Binding. It also helps against planeswalkers, The Scarab God, or Regal Caracal. I feel this match-up is not favored until after sideboarding when we are a slight favorite.
VS. Mono-Red
Out: Dusk Legion Zealot x4, Yahenni, Undying Partisan x1
In: Doomfall x2, Ixalan's Binding x3
I haven't played against Mono-red that much. All our vamp tokens are great because of the lifelink. Our 4-toughness creatures are in the minority and most of our guys will die to burn spells or glorybringer exerts. Ixalan's Binding is very slow, but gives you a lot of insurance against the most annoying recurring threats like Earthshaker Khenra, Rekindling Phoenix, or Hazoret. You can leave some of the bindings out when you are on the play, but I think having them on the draw is important. You have to pressure their life total. Remember that while tokens block very well, if they can live and attack (possibly with a buff!) then they can basically "drain". The zealot comes out here as the life is important, so you will have less card-flow. Try to maximize your synergies and stack lord effects with tokens. I've heard it's a good match-up because of the lifegain, but have only played a couple practice games.
VS. Grixis Energy
Out: Sanctum Seeker x2, Radiant Destiny x1, Legion Lieutenant x2, Call to the Feast x1
In: Duress x2, Doomfall x2, Profane Procession x1, Ixalan's Binding x1
You really want to have answers to The Scarab God, Rekindling Phoenix, and Glorybringer. All 3 of those can stabilize a board and provide them ways to eventually win. Search for Azcanta is also a real problem, make sure to save your field of ruin and don't be afraid to Ixalan's Binding it! Fatal Push is mostly for Glint-Sleeve Siphoner which is otherwise a pain to deal with. Still it isn't great and if you feel like they sided them out, side out the Pushes too. Sometimes I side back into the more aggressive base deck in game three if I'm on the draw since you want to have the most aggressive hands possible, though a couple Duress are always nice for both information and ripping key removal cards. This match-up comes down to whether or not they can stick something that you can't deal with. The discard and exile effects are great, so I feel like it's an alright match-up.
VS. RG Dinos
Out: Sanctum Seeker x1, Call to the Feast x2
In: Slaughter the Strong x2, Arterial Flow x1
The trample really hurts us and makes this a more-difficult deck to stabilize against than it would seem. You absolutely need to be aggressive and deal with Otepec Huntmaster. The Slaughter the Strongs come in to deal with messed up boards involving Carnage Tyrant, Regisaur Alpha, or Ghalta, Primal Hunger. This match-up can feel terrible depending on the draws from the decks. Call to the Feast is often too slow, with the lifegain not mattering as much as in other match-ups.
