Giant Spider

Reach (This creature can block creatures with flying.)

Reclaim

Put target card from your graveyard on top of your library.

Blightwidow

Reach (This creature can block creatures with flying.)
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Aether Web

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1, has reach, and can block creatures with shadow as though they didn't have shadow. (Creatures with reach can block creatures with flying.)

Somberwald Spider

Reach (This creature can block creatures with flying.)
Morbid — This creature enters with two +1/+1 counters on it if a creature died this turn.

Arachnus Web

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.
At the beginning of the end step, if enchanted creature's power is 4 or greater, destroy this Aura.

Pistus Strike

Destroy target creature with flying. Its controller gets a poison counter.

Stingerfling Spider

Reach
When this creature enters, you may destroy target creature with flying.

Forest

Arachnus Spinner

Reach
Tap an untapped Spider you control: Search your graveyard and/or library for a card named Arachnus Web and put it onto the battlefield attached to target creature. If you search your library this way, shuffle.

Tangle Mantis

Plummet

Naturalize

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets +0/+2 and has reach. (It can block creatures with flying.)

Hurricane

Hurricane deals X damage to each creature with flying and each player.

Kavu Climber

Dryad Sophisticate

Nonbasic landwalk (This creature can't be blocked as long as defending player controls a nonbasic land.)

Overrun

Creatures you control get +3/+3 and gain trample until end of turn. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)