Prediction for possible fun RNG subsets of 3:
Rule list:
The thin: 30-card deck
The thick: 40-card deck
The fat: 50-card deck
The Mono: Mono deck
The Duo: Duo deck
The Trio: Trio deck
The resistant: No spells
The wishy-washy: No permanents (other than pillars and pendulums)
The nude: No pillars and no pendulums
The odd: No cards that cost 2, 4, 6, 8, or 10 quantum
The even: No cards that cost 1, 3, 5, 7, or 9 quantum
The prime: No cards that cost 2, 3, 5, or 7 quantum
these would make for quick tourney: all decks are illegal 
as you may choose 2 of 3 rules, only first 2 are correct.. 3-4: pillar only deck would do...whoever wins 1st turn loses 
For the third one, you could have either just novas and creatures or just pillars and creatures. Just pillars and creatures is not a very fun deck to play but it works.
For the last one, going with even/prime (4, 6, 8, 10, 12) or odd/prime (1, 9) would still let you play some cards, just not very many. XD