Definitely worth a look if you have strong EtBs aplenty
Not all cards have been revealed so far, and the only set of cards confirmed at this time is dedicated to Avatar 's cabbage merchant

Ainok Tracker Akroma, Angel of Fury Aphetto Alchemist Aquamorph Entity Ascending Aven Ashcloud Phoenix Aven Liberator Backslide Battering Craghorn Birchlore Rangers Blistering Firecat Bloodstoke Howler Branchsnap Lorian Brine Elemental Broodhatch Nantuko Canyon Lurkers Charging Slateback Chromeshell Crab Coral Trickster Crude Rampart Daru Healer Daru Lancer Daru Mender Daru Sanctifier Dawning Purist Defender of the Order Dermoplasm Disruptive Pitmage Dragon's Eye Savants Dulcet Sirens Dwarven Blastminer Echo Tracer Efreet Weaponmaster Exalted Angel Exiled Doomsayer Fathom Seer Fledgling Mawcor Foothill Guide Fortune Thief Frontline Strategist Gathan Raiders Glacial Stalker Goblin Taskmaster Gravel Slinger Hooded Hydra Horde Ambusher Hystrodon Icefeather Aven Imperial Hellkite Ironfist Crusher Jeering Instigator Karona's Zealot Kheru Spellsnatcher Kin-Tree Warden Krosan Cloudscraper Krosan Colossus Liege of the Axe Lumithread Field Maelstrom Djinn Master of Pearls Master of the Veil Mischievous Quanar Mistfire Weaver Mistform Seaswift Mistform Shrieker Monastery Flock Mystic of the Hidden Way Nameless One Nantuko Vigilante Patron of the Wild Pine Walker Primal Whisperer

Can someone explain the parallel city cards
In decks with cheap removal or pump like Lightning Bolt or Atarka's Command, it snowballs fast by clearing blockers or pushing extra damage
Balthor the Defiled, Karador, Ghost Chieftain, and Chainer, Nightmare Adept are the best commanders that fit into these decks