Drawing cards with enchantments keeps the hand fueled, but the +1/+1 counters from artifacts are even better
Honorable Mentions Spoils of Victory and Farseek can search for Plains, but they can also search for other land types
More often than not, players will have hand traps like Ash Blossom & Joyous Spring, Droll & Lock Bird and, if playing Yu-Gi-Oh
16 card packs, resulting in a 384 card pool for an 8 player draft, have been increasingly popular amongst some Cube designers for largely this reason
This only really matters for things like deck import and export, though
Artificer's Dragon Artificer's Dragon seems cool but for, say, eight mana(?!) you can unearth this and give your team of robots a +3 tramples-less