edhseer Commander synergy, explained
Legendary Planeswalker — Teferi
Mana cost: {4}{U}{U}
Look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.
activated +1 — puts cards into your hand
Untap up to four target permanents.
activated −1 — untaps a permanent
You get an emblem with "You may activate loyalty abilities of planeswalkers you control on any player's turn any time you could cast an instant."
activated −10 — gets an emblem
Teferi, Temporal Archmage can be your commander.
Causes: untap a permanent.
Cares about: nothing.
a permanent untaps — 38 cards in Teferi's colors can cause this (Teferi is one).
When Teferi, Temporal Archmage untaps:
a planeswalker is cast — 56 cards in Teferi's colors can cause this (Teferi is one).
When Teferi, Temporal Archmage is cast:
70 other cards care about it too. These are the ones with the most connections.
a planeswalker enters the battlefield — 48 cards in Teferi's colors can cause this (Teferi is one).