Arcane Signet

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

Tocasia, Dig Site Mentor

Creatures you control have vigilance and "{T}: Surveil 1." (To surveil 1, look at the top card of your library. You may put that card into your graveyard.)
{2}{G}{G}{W}{W}{U}{U}, Exile this card from your graveyard: Return any number of target artifact cards with total mana value 10 or less from your graveyard to the battlefield. Activate only as a sorcery.

Mishra's Bauble

{T}, Sacrifice this artifact: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.