Tsagan, Raider Warlord

Double strike
Start your engines!
Whenever Tsagan attacks, creatures you control get +1/+0 until end of turn for each creature you control with first strike or double strike.
Max speed — Tsagan has deathtouch. Other creatures you control have first strike.

Sol Ring

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Arcane Signet

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