Heirloom Blade
Artifact — Equipment
Equipped creature gets +3/+1.
Whenever equipped creature dies, you may reveal cards from the top of your library until you reveal a creature card that shares a creature type with it. Put that card into your hand and the rest on the bottom of your library in a random order.
Equip 
Carmen Sinek
The List (PLST)
• #C17-52Rulings
If Heirloom Blade leaves the battlefield at the same time that the equipped creature dies, its triggered ability triggers.
(wotc • 2017-08-25)
You'll reveal cards until you find one that shares at least one creature type with the creature that died. For example, if a Cat Wizard dies, you'll stop if you reveal a Human Wizard or Cat Soldier.
(wotc • 2017-08-25)
If the equipped creature has no creature type, no card can share a creature type with it.
(wotc • 2017-08-25)
"Artifact" isn't a creature type.
(wotc • 2017-08-25)
Compare the revealed cards to the creature as it last existed before it died, not to the creature card as it exists in its owner's graveyard, to determine which one you put into your hand.
(wotc • 2017-08-25)
If you don't reveal a creature card that shares a type with the creature that died, you'll just reveal and randomize your library.
(wotc • 2017-08-25)
Rulings
If Heirloom Blade leaves the battlefield at the same time that the equipped creature dies, its triggered ability triggers.
(wotc • 2017-08-25)
You'll reveal cards until you find one that shares at least one creature type with the creature that died. For example, if a Cat Wizard dies, you'll stop if you reveal a Human Wizard or Cat Soldier.
(wotc • 2017-08-25)
If the equipped creature has no creature type, no card can share a creature type with it.
(wotc • 2017-08-25)
"Artifact" isn't a creature type.
(wotc • 2017-08-25)
Compare the revealed cards to the creature as it last existed before it died, not to the creature card as it exists in its owner's graveyard, to determine which one you put into your hand.
(wotc • 2017-08-25)
If you don't reveal a creature card that shares a type with the creature that died, you'll just reveal and randomize your library.
(wotc • 2017-08-25)