Prismatic had the right idea where it banned fast mana like Mana Crypt and Sol Ring, tutors (ranging from Mystical Teachings to Demonic Tutor), and then any other degenerate cards like Memory Jar, Necropotence, Yawgmoth's Will, or Gush
Jenson Carthalion, Druid Exile Jenson Carthalion, Druid Exile rewards you for casting multicolored spells by letting you scry 1, and if that spell is all colors, you get a free 4/4 Angel with flying and vigilance
Into the Inklands I Will Find My Way card costs only a single ink, meaning that any character costing one or more can be exerted to sing the card for free
You can find these Buy-a-box promos at certain local game stores
This means anyone who wants a Blooming Waters Premium Collection will likely want to be at their local retailers the day it releases
They are the top competition for their respective slots