Landless Chaos Cube
Any extra cards from the draft are turned into a "Land" deck, which act as all 5 basic types at once.
Players may play one land from their hands in addition to a land from the land deck each turn.
Wild Cards cost 3 colorless, and use the Scryfall random feature to determine which card is actually played.
When these cards go to the graveyard they revert to being Wild Cards, which are sorceries.
If a spell would send a facedown land from the lands deck to a graveyard, hand, exile, or deck, it goes to these zones as a face up version of itself (The land now counts as whatever the face of the card is and is treated as a normal card)