If you are familiar with White Weenie skip the first part.
White Weenie is an old, solid archetype based around swarming the field with small white creatures. It is comprised of creatures, creature bonuses, and generally anything that synergizes with lots of small creatures.
The reason I moved Esper is because there is no draw engines for WW anywhere in standard.
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I will now explain both mainboard and sideboard.
MAINBOARD:
Creatures:
Blood Scrivener - WW tends to run out of hand fast, making this a great source of refuel.
Brimaz, King of Oreskos - Everything WW wants and is on a stick.
Frontline Medic - Mass indestructibility is nothing to sneeze at, with the added benefit of killing Sphinx's Rev.
Xathrid Necromancer - Makes removal ALOT less potent.
Judge's Familiar - 1 drop that is easy on the mana base, evasive, and locking out early spells is a good card in my book.
Pack Rat - Pitching useless lands for creatures at instant speed is a great thing in WW
and given doing so makes the rats stronger, SHAMWOW!
Realmwright - Very necessary fixing in an aggressive three color deck with a body attached.
Soldier of the Pantheon - Just a super solid one drop.
Enchantments:
Path of Bravery - Mass buffs with life gain makes this just what we need to win.
Instants:
Far // Away - Diverse removal, beats hexproof.
Hero's Downfall - Black removal at its finest in standard, probably why its 12$.
(Legendary) Enchantment Artifacts:
Bident of Thassa - When you need cards, you know what to use, BIDENT OF THASSA!
(Bad Ghostbusters reference)
Spear of Heliod - Mass creature buffs, and removeal? What have you done Wizards?
(Legendary) Enchantment Creatures:
Ephara, God of the Polis - If you know Mentor the Meek, you can catch my drift here. If not, look him up.
Land Base:
Shock heavy because, THIS IS AGGRO!!! (If you know the reference, comment what it is)
SIDEBOARD:
Artifacts:
Elixir of Immortality - Use against mill.
Pithing Needle - Destroys planeswalkers, mutavault, and pack rat, but more importantly, Aetherling...
Instants:
Negate - Use against Sphinx's Revelation, Elspeth, Detention Sphere, and anything control.
Far // Away - See above.
Hero's Downfall - See above.
Sorcery:
Thoughtseize - Super good in general, sideboard as you feel comfortable.
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Sideboarding:
One thing to note when sideboarding in general is to replace the card who the card you are putting in replaces in role or replace the card that has negative synergy with the card you are inserting. For example, if I put in my negates, I will mot likely take out my Blood Scriveners, for I will be holding cards in hand.
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Budgeting:
If you are considering buying this deck, but can't match the price, here are some changes to make it much cheaper.
-2 Brimaz
-2 Hero's Downfall
-5 Temples
+2 Fiendslayer Paladin
+2 Ultimate Price/Doom Blade (Depending on local meta)
+5 Guildgates/Basic Lands (Whatever works for you)