+2 Mace

Equipped creature gets +2/+2.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Abdel Adrian, Gorion's Ward

When Abdel Adrian, Gorion's Ward enters, exile any number of other nonland permanents you control until Abdel Adrian leaves the battlefield. Create a 1/1 white Soldier creature token for each permanent exiled this way.
Choose a Background (You can have a Background as a second commander.)

Archpriest of Iona

Archpriest of Iona's power is equal to the number of creatures in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)
At the beginning of combat on your turn, if you have a full party, target creature gets +1/+1 and gains flying until end of turn.

Baldur's Gate

{T}: Add {C}.
{2}, {T}: Add X mana of any one color, where X is the number of other Gates you control.

Arcane Signet

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

Nadaar, Selfless Paladin

Vigilance
Whenever Nadaar, Selfless Paladin enters or attacks, venture into the dungeon. (Enter the first room or advance to the next room.)
Other creatures you control get +1/+1 as long as you've completed a dungeon.