This is the 3 Card Blind Custom Cube. I only added a few custom cards to complete cycles, fill holes that current cards can't, and add a little more interesting stuff.

What is 3 Card Blind? In 3 Card Blind, you play with 3 cards in your hand and no library. Players don't lose the game when drawing from an empty library. Rather than playing best of 2, since all matchups are deterministic and pretty easily solvable, you play one game on the play and one game on the draw.

In addition to the above, players play with their hands revealed, and all random effects are decided by the opponent of the controller of the random effect. (For example, if you have a Crystalline Giant on the board, your opponent will decide which counter to put on it at the beginning of your combat)

Players draft 1 pack of 15 cards and must draft all their mana sources. No basics will be given after the draft.

After drafting, each player makes a main deck that they will play games 1 and 2 with against each other player. After playing a game on the play and on the draw against a player, both players get a chance to sideboard before playing another 2 games. Players may reuse any number of cards from their first deck when making their second and can even submit the same deck for all their games, but sideboarding into a whole new deck to counter somebody is very viable in this format especially when your pool is 5 times the size of your deck.