Tier S Let's start with these three Rakdos leaders
This card provides commander protection, mana support, and easy ways to move your equipment or auras around
Platinum Angel Now that's what I call a platinum ability
For sheer efficiency and value, its hard to beat Rancor or Ethereal Armor
Sygg, River Cutthroat At the very least, Sygg, River Cutthroat earns points for being one of the few truly aggressive Dimir commanders
Creatures (6) Arboreal Grazer x4 Subtlety x2 Instants (18) Lightning Bolt x3 Counterspell x4 Planar Genesis x4 Expansion / Explosion x3 Nexus of Fate x4 Sorcery (4) Gates Ablaze x4 Enchantments (7) Guild Summit x4 Wilderness Reclamation x3 Lands (25) Azorius Guildgate Breeding Pool x2 Gruul Guildgate x4 Island Izzet Guildgate x4 Misty Rainforest x2 Scalding Tarn x2 Simic Guildgate x4 Steam Vents x2 Thran Portal x3 Sideboard (15) Consign to Memory Haywire Mite x2 Spell Pierce x2 Swan Song Damping Sphere x2 Dismember x2 Gatebreaker Ram x4 Force of Vigor I won't pretend that this is the most competitive Modern deck in the world, but it's a riff on a deck I loved playing in the Standard, and it gives you a pretty good idea of how a gates deck wants to play
