B/U/G Control

Main Board Explanation:

Creatures:
Reaper of the Wilds: lets you smooth out draws and kill their things
Dec Demon: Big ass beater that makes them sack
Prophet of Kruphix: Untaps lands and creatures giving you blocker each turn plau mana for kill spells and counters
Sylvan Caryatid: Mana fixing blocker that they can't tough
Aetherling: Finisher

Instants:
Dissolve: Scrying cancel
Syncopate: Mana sink counter spell
Hero's Downfall: BOOM down goes the planeswalker
Putrefy: Kills creatures and artifacts
Abrupt Decay: Planeswalker and 3 CMC killer

Sorcery:
Graze of Granite: Board-wipe (I hate this card TBH)

Planeswalker:
Jace, Architect of Thought: Mini Fact or Fiction each turn for that card advantage, plus the tick up to slow aggro. Also at 8 you can steal their threats for the win
Kiora: Gives you the extra land drop if you need, also makes a Reckoner worthless, plus that ult is a winner
Vraska: Can win games plus she has a spot removal on her with that minus 3

Land:
Pretty straight forward for a three color deck. Smooth out draws with the temples.

Sideboard Explanation:

Artifacts:
Pithing Needle: Planeswalker and Nykthos shrine to Nyx neuterer
Ratchet Bomb: BOOM!

Planeswalker:
Ashiok: Mill cards and put it in for mirror matches or other control matches
Jace, Memory Adept: Mill. That's all.

Instants:
Gainsay: Side in for Blue control and mono blue devotion decks
Essence Scatter: Good against R/G Monsters and other creature decks
Negate: Side in against control decks

Creatures:
Aetherling: Add this against control match ups for another beater

If you can't figure that out from the description, you probably shouldn't play this.

• BUG
• Control
• Standard
• good