Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Mana Confluence

{T}, Pay 1 life: Add one mana of any color.

Tamiyo, Field Researcher

+1: Choose up to two target creatures. Until your next turn, whenever either of those creatures deals combat damage, you draw a card.
−2: Tap up to two target nonland permanents. They don't untap during their controller's next untap step.
−7: Draw three cards. You get an emblem with "You may cast spells from your hand without paying their mana costs."

Onakke Oathkeeper

Creatures can't attack planeswalkers you control unless their controller pays {1} for each creature they control that's attacking a planeswalker you control.
{4}{W}{W}, Exile Onakke Oathkeeper from your graveyard: Return target planeswalker card from your graveyard to the battlefield.