Snarespinner

Reach
Whenever Snarespinner blocks a creature with flying, Snarespinner gets +2/+0 until end of turn.

Hatchery Spider

Reach
Undergrowth — When you cast this spell, reveal the top X cards of your library, where X is the number of creature cards in your graveyard. You may put a green permanent card with mana value X or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

Spidery Grasp

Untap target creature. It gets +2/+4 and gains reach until end of turn. (It can block creatures with flying.)

Aerial Predation

Destroy target creature with flying. You gain 2 life.

Twin-Silk Spider

Reach
When Twin-Silk Spider enters, create a 1/2 green Spider creature token with reach.

Swarmyard

{T}: Add {C}.
{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Grappler Spider

Reach (This creature can block creatures with flying.)

Web Shot

Destroy target creature with flying. (Then exile this card. You may cast the creature later from exile.)

Ettercap

Ettercap // Web Shot

Mammoth Spider

Netcaster Spider

Reach (This creature can block creatures with flying.)
Whenever Netcaster Spider blocks a creature with flying, Netcaster Spider gets +2/+0 until end of turn.

Shelob, Child of Ungoliant

Deathtouch, ward {2}
Other Spiders you control have deathtouch and ward {2}.
Whenever another creature dealt damage this turn by a Spider you controlled dies, create a token that's a copy of that creature, except it's a Food artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life," and it loses all other card types.

Dawnhart Rejuvenator

When Dawnhart Rejuvenator enters, you gain 3 life.
{T}: Add one mana of any color.

Watcher in the Web

Reach (This creature can block creatures with flying.)
Watcher in the Web can block an additional seven creatures each combat.