One of the many new goodies brought by WAR is multiple ways to repeatedly proliferate, particularly on low-cost permanents. There are a ton of different ways to use these tools, but this is the first one I came up with which is both very different from the proliferate decks enables by New Phyrexia and at least moderately interesting and fuctional.
This list does still suffer from some inconsistency and fragility however. The depletion lands offer great power but if your early proliferate creatures are removed they can become a liability. There's also the problem of drawing too few enablers or too few payoffs, and the card draw in the deck is all dependent on having your synergies up and running. Consistent colored mana can be tricky as well since there are so many highly desirable colorless lands and 8 ETBT lands which do not fix colors. When the pieces do come together it's a ton of fun to fiddle with all the different counters and bury opponents in value!
Yahenni's Expertise looks amazing. To use it optimally you'll want to make sure you have enough card advantage that the tempo is invaluable and you always have options remaining in hand. Phyrexian Arena, Compulsive Research, Thirst for Knowledge, and Trade Secrets are great at keeping the hand full for exactly 3 CMC. It also has excellent synergy with 3 mana planeswalkers since you can clear the field of potential attackers and safely drop the walker in one turn. Honestly though, any strong card at 2-3 mana goes well with it...
1
4 Thrummingbird
1 Mikaeus, the Lunarch
4 Flux Channeler
2 Mindless Automaton
1 Azor's Elocutors
1 Contentious Plan
4 Everflowing Chalice
2 Orochi Hatchery
1 Ajani Goldmane
4 Parallax Wave
4 Pursuit of Knowledge
4 Contagion Engine
1 Calciform Pools
1 Grasping Dunes
4 Irrigated Farmland
3 Karn's Bastion
4 Remote Farm
4 Saprazzan Skerry
1 Island
2 Plains
New additions Grateful Apparition and Flux Channeler join mainstay Thrummingbird in providing enough cheap, consistent, repeatable proliferaters to make depletion lands playable, while supercharging resource engines like Everflowing Chalice and Mindless Automaton. Parallax Wave and Contagion Engine provide powerful multiplayer removal while Pursuit of Knowledge easily draws seven after skipping just one draw. A juiced up Orochi Hatchery or random value creatures pumped up huge by Mikaeus, the Lunarch or Ajani Goldmane serve as the primary win condition, while Azor's Elocutors can often win the game after just one upkeep in the late game
This list does still suffer from some inconsistency and fragility however. The depletion lands offer great power but if your early proliferate creatures are removed they can become a liability. There's also the problem of drawing too few enablers or too few payoffs, and the card draw in the deck is all dependent on having your synergies up and running. Consistent colored mana can be tricky as well since there are so many highly desirable colorless lands and 8 ETBT lands which do not fix colors. When the pieces do come together it's a ton of fun to fiddle with all the different counters and bury opponents in value!
1
Yahenni's Expertise looks amazing. To use it optimally you'll want to make sure you have enough card advantage that the tempo is invaluable and you always have options remaining in hand. Phyrexian Arena, Compulsive Research, Thirst for Knowledge, and Trade Secrets are great at keeping the hand full for exactly 3 CMC. It also has excellent synergy with 3 mana planeswalkers since you can clear the field of potential attackers and safely drop the walker in one turn. Honestly though, any strong card at 2-3 mana goes well with it...
Quicksmith Rebel could be a fun casual build-around with artifacts that untap themselves repeatedly. Pili-Pala and Staff of Domination stand out immediately but Grinding Station, Blasting Station, Honor-Worn Shaku, and Phyrexian Ironfoot could all lead a deck in interesting niche directions.