Modern, "can block only creatures with flying" (27)
Flash
Flying
Brazen Borrower can block only creatures with flying.
Cipherbound Spirit can block only creatures with flying.
: Draw two cards, then discard a card.
Cloud Elemental can block only creatures with flying.
Flying (This creature can't be blocked except by creatures with flying or reach.)
Cloud Sprite can block only creatures with flying.
, , Discard a card: Create a 1/1 blue Faerie creature token named Cloud Sprite. It has flying and "Cloud Sprite can block only creatures with flying."
Creatures with flying can block only creatures with flying.
Departed Soulkeeper can block only creatures with flying.
If Departed Soulkeeper would be put into a graveyard from anywhere, exile it instead.
Dreamcaller Siren can block only creatures with flying.
When Dreamcaller Siren enters, if you control another Pirate, tap up to two target nonland permanents.
Etherium Pteramander can block only creatures with flying.
: Adapt 4. This ability costs less to activate for each other artifact you control. (If this creature has no +1/+1 counters on it, put four +1/+1 counters on it.)
Return all creatures to their owners' hands. For each opponent who controlled a creature returned this way, you create two 1/1 blue Faerie creature tokens with flying and "This creature can block only creatures with flying."
Reach
Gloomwidow can block only creatures with flying.
Hoverguard Observer can block only creatures with flying.
Draw three cards. Create a 1/1 blue Faerie creature token with flying and "This creature can block only creatures with flying."
Long-Finned Skywhale can block only creatures with flying.
When Ominous Roost enters and whenever you cast a spell from your graveyard, create a 1/1 blue Bird creature token with flying and "This creature can block only creatures with flying."
Return target nonland permanent an opponent controls to its owner's hand.
Scrapskin Drake can block only creatures with flying.
Shacklegeist can block only creatures with flying.
Tap two untapped Spirits you control: Tap target creature you don't control.
Skywinder Drake can block only creatures with flying.
Stormbound Geist can block only creatures with flying.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)
Stormcloud Djinn can block only creatures with flying.
: Stormcloud Djinn gets +2/+0 until end of turn and deals 1 damage to you.
Stratozeppelid can block only creatures with flying.
Enchant creature
When Stratus Walk enters, draw a card.
Enchanted creature has flying. (It can't be blocked except by creatures with flying or reach.)
Enchanted creature can block only creatures with flying.
Tattered Haunter can block only creatures with flying.
Vaporkin can block only creatures with flying.
Wanderlight Spirit can block only creatures with flying.
Welkin Tern can block only creatures with flying.
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