Each Challenger Deck 2019 - 60 card main deck with a 15 card sideboard 

Creature (13)

4 Goblin Electromancer

4 Crackling Drake

2 Murmuring Mystic

1 Arclight Phoenix

2 Niv-Mizzet, Parun

Sorcery (9)

4 Chart a Course

4 Lava Coil

1 Beacon Bolt

Instant (15)

4 Opt

4 Radical Idea

4 Shock

2 Dive Down

1 Blink of an Eye

Enchantment (1)

1 The Mirari Conjecture

Land (22)

3 Sulfur Falls

4 Izzet Guildgate

8 Island

7 Mountain

60 Cards

Sideboard (15)

1 The Mirari Conjecture  1 Beacon Bolt 3 Negate  3 Entrancing Melody 3 Fiery Cannonade  2 Shivan Fire 2 Disdainful Stroke