Jawbone Duelist

Double strike
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)

Twinblade Invocation

Enchant creature
Enchanted creature has double strike.
If Twinblade Invocation would be put into a graveyard from anywhere, exile it instead.

Twinblade Geist

Double strike
Disturb {2}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Twinblade Geist // Twinblade Invocation

Illuminator Virtuoso

Double strike
Whenever this creature becomes the target of a spell you control, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Fencing Ace

Double strike (This creature deals both first-strike and regular combat damage.)

Swiftblade Vindicator

Double strike (This creature deals both first-strike and regular combat damage.)
Vigilance (Attacking doesn't cause this creature to tap.)
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Viashino Slaughtermaster

Double strike
{B}{G}: This creature gets +1/+1 until end of turn. Activate only once each turn.

Warren Instigator

Double strike
Whenever this creature deals damage to an opponent, you may put a Goblin creature card from your hand onto the battlefield.

Boros Swiftblade

Kor Blademaster

Double strike
Equipped Warriors you control have double strike.

Lizard Blades

Double strike
Equipped creature has double strike.
Reconfigure {2} ({2}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Adorned Pouncer

Double strike
Eternalize {3}{W}{W} ({3}{W}{W}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Cat with no mana cost. Eternalize only as a sorcery.)