Swiftfoot Boots
Artifact — Equipment
Equipped creature has hexproof and [[ keyword: "haste" ]].
Equip 
"I don't need brakes. I usually find that if something stops me, it's interesting enough to stop for."
Zezhou Chen
Fallout (PIP)
• #770Rulings
If a creature enters the battlefield under your control and gains haste, but then loses it before attacking, it won't be able to attack that turn. This means that you can't use one Swiftfoot Boots to allow two new creatures to attack in the same turn.
(wotc • 2018-03-16)
Rulings
If a creature enters the battlefield under your control and gains haste, but then loses it before attacking, it won't be able to attack that turn. This means that you can't use one Swiftfoot Boots to allow two new creatures to attack in the same turn.
(wotc • 2018-03-16)