When a "Blackwing" monster is Normal Summoned to your side of the field: You can add 1 "Blackwing" monster from your Deck to your hand with less ATK than that monster.
Here are the monster you can summon to trigger the effect of Black Whirlwind and are also the monsters you can search with its effect.
Tetsu Trudge Unlock Event
2nd Anniversary Campaign
Selection Box Vol. 02
New Week Campaign!
Train Your Kuriboh! Campaign
PvP Best decks [21 Jan Updated]
King of Game decks [Jan 2019]
How to beat/farm Official Tetsu Trudge Lvl40
Tetsu Unlock Event: Sector Security on the Move! Officer Tetsu Trudge
Koa'ki Meiru: deck recipe (After 28 Dec)
Dark Magician: deck recipe (After 2019 Jan)
Leaked News [Jan 18 updated]
Geargia: deck recipe (After 2019 Jan)
Obelisk the Tormentor: deck recipe
Masked HERO: deck recipe
Silent Swordsman BLS: deck recipe
Sphere Kuriboh | Deck and Rulings
Ancient Rules | Deck and Rulings
Wall of Disruption | Deck and Rulings
Gozuki | Deck and Rulings
Floodgate Trap Hole | Decks and Ruling