Five-Color Niv-Mizzet (Yorion)
A Pioneer deck, by BobTheDog
2nd place at a tournament in Magic Online on 2020-08-09

Maindeck:

Creatures
3 Deathrite Shaman
4 Sylvan Caryatid

Instants
2 Abrupt Decay
2 Fatal Push
1 Utter End

Legendary Creatures
4 Niv-Mizzet Reborn
1 Tolsimir, Friend to Wolves
4 Uro, Titan of Nature's Wrath (Banned in Pioneer)

Legendary Enchantments
2 Oath of Kaya
4 Oath of Nissa

Legendary Planeswalkers
2 Nahiri, the Harbinger
4 Teferi, Time Raveler (Banned in Pioneer)

Sorceries
4 Bring to Light
4 Dreadbore
1 Extinction Event
1 Rakdos's Return
1 Solar Blaze

Basic Lands
1 Forest
1 Island
1 Mountain
1 Plains
1 Swamp

Lands
2 Breeding Pool
3 Drowned Catacomb
4 Fabled Passage
2 Hallowed Fountain
4 Indatha Triome
2 Ketria Triome
1 Mana Confluence
3 Overgrown Tomb
1 Raugrin Triome
1 Savai Triome
2 Steam Vents
2 Stomping Ground
2 Sunpetal Grove
1 Temple Garden
1 Zagoth Triome

Sideboard:
3 Izzet Staticaster
4 Voice of Resurgence
1 The Scarab God
1 Yorion, Sky Nomad
1 Casualties of War
1 Hour of Devastation
1 Rakdos's Return
1 Slaughter Games
1 Thought Erasure
1 Thoughtseize