Zendikar Rising

Instant

Sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Roiling Regrowth

This is the actual decklist that I own.
Draft the Commanders first from a special pool (in the sideboard) with 4 packs of 10 or 12.
Each commander has partner. If you want to use one of the companions, you can do that as well if you abide by the companion rules and color identity rules. For Umori specifically, you may still have creatures as your commanders as long as the rest of the deck follows its companion rules.
I suggest choosing your commanders (and sometimes a companion) before you've drafted from the main pool. 
Each player automatically gets a command tower and an arcane signet.
Before drafting, players can decide if they want to draft 60 card commander decks or full-sized 100 card decks.
Draft 4 packs of 14 for 60 card decks and 6 or 7 packs of 14 for 100 card decks.
Color Identity does not matter when it comes to lands.
Draft Archetypes:
Reanimator
Cast spell, get value
Freecasting
Theft
Copying spells
Value for targeting your own creatures

(The Real) Budget Spellslinger Commander Cube

All the Lands be Falling

​Strain Echo - [Mucormycosis]
Virulenance: 6.5/10
Pathology: A highly resilient fungal overgrowth. It possessed excellent resource-conversion metrics but a lethargic incubation period. It required 4 to 6 replication cycles to achieve lethality—too slow for the current meta-environment.

Fungus

Obuun, Mal Daya Ancestor

Atomic

Source: https://magic.wizards.com/en/news/announcements/edge-of-eternities-commander-decklists

Roiling Regrowth

Rules Text

Card Facts

Legality

Rulings

Every version

Decks using this card