A prototype for an idea that my friends and I had: Commander cube draft! This is a singleton cube with special rules for drafting and pack creation.
Rules
The draft is split into two parts: commander draft and deck draft. The commander draft is a single round at the beginning of the draft where the players draft 4-card packs(???) of legendary creatures, which the players will use as commanders. This is followed by the deck draft, in which the players do a 5-round draft with 15-card packs for a total of 75 cards in each player's pool.
Info
The packs in this cube will not be sorted by rarity like real booster packs are, but they will also not be completely random either. We plan on sorting the cards into several categories, each of which will be focused on a certain type of card. Each pack will then contain a set number of cards from each category (though some categories may get more slots than others). For example, one category might be for cards that help with mana bases and have more mana rocks and lands than other categories. However, not all or even most of the cards would necessarily fit this theme; the categories are intended to make sure everyone gets enough cards to build a good deck while still having a large degree of randomness.