Goblins and elves are more consistent tribal decks but far fewer cards are cube worthy on their own
Unlike The First Chapter, it seems we've got a bit more supply with Rise of the Floodborn, so there are more cards in the market
While Ive never actually seen someone do the same with a Commander deck, it could certainly be done, and it would be a much cheaper alternative that comes with a story every time you sit down to play it
Then when it deals damage you get to tick up your Ring emblem and THEN discard your hopefully empty hand and draw 4 which is just incredibly powerful
This creates a small space to explore what I call gimmick decks in the Alpha League, a design space generally that does not exist anywhere else in constructed Magic (although, on occasions, can occur in Limited contexts, which obey the original rules of Magic: 40 card minimums, and no unique card caps)
Since it's already in the game, trainers predict that it will be coming pretty soon