360 card cube
3 copies of commons, 2 copies of each non-legendary uncommon, and 1 of each relevant rare and legendary creature. some exceptions may apply

There are a few more powerful options, but also more answers to those options to handle the threat

color combo explanations:
: Halflings/Food
: Draw 2/turn, birds, flying
: Humans 1/1 Human Soldier tokens with Equipment/Spells
: A little bit of tokens, food, and removal
: Amass, tempo control, bounce, card draw
: Instant/sorcery spells
: Scry
: Amass aggro, menace, sacrifice and removal
: Mostly Trees, with Elves, Orcs and removal
: Ramp, 4 power matters, Fight/Bite

All colors have access to Ring Tempting, perhaps have more than others.

2-color decks are norm,
3-color decks allow a healthy number of powerful legends to be played.
4+ color decks are even possible