Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. This artifact deals 1 damage to you.

Drumbellower

Flying
Untap all creatures you control during each other player's untap step.

Hallowed Fountain

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

Command Tower

Meticulous Archive

({T}: Add {W} or {U}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Gideon, Martial Paragon

+2: Untap all creatures you control. Those creatures get +1/+1 until end of turn.
0: Until end of turn, Gideon becomes a 5/5 Human Soldier creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.
−10: Creatures you control get +2/+2 until end of turn. Tap all creatures your opponents control.

Flooded Strand

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Call the Gatewatch

Search your library for a planeswalker card, reveal it, put it into your hand, then shuffle.

Dramatic Reversal

Untap all nonland permanents you control.

Niambi, Faithful Healer

When Niambi enters, you may search your library and/or graveyard for a card named Teferi, Timebender, reveal it, and put it into your hand. If you search your library this way, shuffle.

Sol Ring

Teferi, Timebender

+2: Untap up to one target artifact or creature.
−3: You gain 2 life and draw two cards.
−9: Take an extra turn after this one.