Tundra

Tameshi, Reality Architect

Whenever one or more noncreature permanents are returned to hand, draw a card. This ability triggers only once each turn.
{X}{W}, Return a land you control to its owner's hand: Return target artifact or enchantment card with mana value X or less from your graveyard to the battlefield. Activate only as a sorcery.

Seat of the Synod

Ancient Den

Karakas

{T}: Add {W}.
{T}: Return target legendary creature to its owner's hand.

Spellseeker

When Spellseeker enters, you may search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

Mishra's Workshop

{T}: Add {C}{C}{C}. Spend this mana only to cast artifact spells.

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters tapped unless you control three or more other Islands.
When Mystic Sanctuary enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Time Walk

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.