Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Sol Ring

Command Tower

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

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Eternal Witness

When Eternal Witness enters the battlefield, you may return target card from your graveyard to your hand.

Tayam, Luminous Enigma

Each other creature you control enters the battlefield with an additional vigilance counter on it.
{3}, Remove three counters from among creatures you control: Mill three cards, then return a permanent card with mana value 3 or less from your graveyard to the battlefield.