Arcane Signet

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

Mark of Sakiko

Enchant creature
Enchanted creature has "Whenever this creature deals combat damage to a player, add that much {G}. Until end of turn, you don't lose this mana as steps and phases end."

Strong Back

Enchant creature
Equip abilities you activate that target enchanted creature cost {3} less to activate.
Aura spells you cast that target enchanted creature cost {3} less to cast.
Enchanted creature gets +2/+2 for each Aura and Equipment attached to it.

Thran Power Suit

Equipped creature gets +1/+1 for each Aura and Equipment attached to it and has ward {2}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Kosei, Penitent Warlord

As long as Kosei is enchanted, equipped, and has a counter on it, Kosei has "Whenever Kosei deals combat damage to an opponent, you draw that many cards and Kosei deals that much damage to each other opponent."

Silent Arbiter

No more than one creature can attack each combat.
No more than one creature can block each combat.