I'm also wondering if there's any way to take advantage of the colorless mana generation, perhaps by naming a basic land
The total number of MTG cards depends on what Magic: The Gathering card count you want to use there are around 27,000 unique cards, but many more if you start to include reprints, variants, and out of game cards like art cards and tokens
2 Vanquisher's Banner Vanquisher's Banner is a five-drop artifact that works well in a variety of tribal decks, from Elf and Zombie to Dragon and Vampire, among others
Having a designer pick you out a rack of jackets gets closer to what Arena Cube is like, so theres no shame in checking out the guide
Screeching ScorchbeastScreeching Scorchbeast gives each player two Rad counters when it attacks, and makes you a bunch of tokens when nonland cards are milled
but at the same time, if your synergy is sound, you can put together some solid decks within the limitations, and then reap the rewards of these powerful new Glimmers