Ember Weaver

Reach (This creature can block creatures with flying.)
As long as you control a red permanent, Ember Weaver gets +1/+0 and has first strike.

Thantis, the Warweaver

Vigilance, reach
All creatures attack each combat if able.
Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Thantis, the Warweaver.

Wilson, Refined Grizzly

This spell can't be countered.
Vigilance, reach, trample
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Choose a Background (You can have a Background as a second commander.)

Giant Spider

Reach (This creature can block creatures with flying.)

Skysnare Spider

Vigilance (Attacking doesn't cause this creature to tap.)
Reach (This creature can block creatures with flying.)

Silklash Spider

Reach
{X}{G}{G}: Silklash Spider deals X damage to each creature with flying.

Grappler Spider

Ishkanah, Grafwidow

Reach
Delirium — When Ishkanah, Grafwidow enters the battlefield, if there are four or more card types among cards in your graveyard, create three 1/2 green Spider creature tokens with reach.
{6}{B}: Target opponent loses 1 life for each Spider you control.

Plated Spider

Kessig Recluse

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Arachnoid

Somberwald Spider

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

Glowstone Recluse

Mutate {3}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Reach
Whenever this creature mutates, put two +1/+1 counters on it.

Funnel-Web Recluse

Reach
Morbid — When Funnel-Web Recluse enters the battlefield, if a creature died this turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Forest

Sentinel Spider

Obelisk Spider

Reach
Whenever Obelisk Spider deals combat damage to a creature, put a -1/-1 counter on that creature.
Whenever you put one or more -1/-1 counters on a creature, each opponent loses 1 life and you gain 1 life.

Woolly Spider

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

Frostweb Spider

Reach (This creature can block creatures with flying.)
Whenever Frostweb Spider blocks a creature with flying, put a +1/+1 counter on Frostweb Spider at end of combat.

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.

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.

Stingerfling Spider

Reach
When Stingerfling Spider enters the battlefield, you may destroy target creature with flying.

Hitchclaw Recluse

Mammoth Spider

Canopy Spider

Sporeweb Weaver

Reach, hexproof from blue
Whenever Sporeweb Weaver is dealt damage, you gain 1 life and create a 1/1 green Saproling creature token.

Juvenile Gloomwidow

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

Arasta of the Endless Web

Reach
Whenever an opponent casts an instant or sorcery spell, create a 1/2 green Spider creature token with reach.

Pincer Spider

Kicker {3} (You may pay an additional {3} as you cast this spell.)
Reach (This creature can block creatures with flying.)
If Pincer Spider was kicked, it enters the battlefield with a +1/+1 counter on it.

Tangle Spider

Flash (You may cast this spell any time you could cast an instant.)
Reach (This creature can block creatures with flying.)

Steam Spitter

Reach (This creature can block creatures with flying.)
{R}: Steam Spitter gets +1/+0 until end of turn.

Webspinner Cuff

Reach
Equipped creature gets +1/+4 and has reach.
Reconfigure {4} ({4}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Aquastrand Spider

Graft 2 (This creature enters the battlefield with two +1/+1 counters on it. Whenever another creature enters the battlefield, you may move a +1/+1 counter from this creature onto it.)
{G}: Target creature with a +1/+1 counter on it gains reach until end of turn. (It can block creatures with flying.)

Rib Cage Spider

Oran-Rief Recluse

Kicker {2}{G} (You may pay an additional {2}{G} as you cast this spell.)
Reach (This creature can block creatures with flying.)
When Oran-Rief Recluse enters the battlefield, if it was kicked, destroy target creature with flying.

Swift Spinner

Graverobber Spider

Reach
{3}{B}: Graverobber Spider gets +X/+X until end of turn, where X is the number of creature cards in your graveyard. Activate only once each turn.

Goliath Spider

Web Shot

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

Ettercap

Ettercap // Web Shot

Twin-Silk Spider

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

Spitting Spider

Reach (This creature can block creatures with flying.)
Sacrifice a land: Spitting Spider deals 1 damage to each creature with flying.

Sweet-Gum Recluse

Flash
Cascade
Reach
When Sweet-Gum Recluse enters the battlefield, put three +1/+1 counters on each of any number of target creatures that entered the battlefield this turn.

Jungle Weaver

Reach (This creature can block creatures with flying.)
Cycling {2} ({2}, Discard this card: Draw a card.)

Chainweb Aracnir

Reach
When Chainweb Aracnir enters the battlefield, it deals damage equal to its power to target creature with flying an opponent controls.
Escape—{3}{G}{G}, Exile four other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)
Chainweb Aracnir escapes with three +1/+1 counters on it.

Watcher in the Web

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

Gnottvold Recluse

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.

Sporecap Spider

Acid Web Spider

Reach
When Acid Web Spider enters the battlefield, you may destroy target Equipment.

Root Spider

Whenever Root Spider blocks, it gets +1/+0 and gains first strike until end of turn.

Snarespinner

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

Deadly Recluse

Gloomwidow

Reach
Gloomwidow can block only creatures with flying.

Cloakwood Hermit

Commander creatures you own have "At the beginning of your end step, if a creature card was put into your graveyard from anywhere this turn, create two tapped 1/1 green Squirrel creature tokens."

Penumbra Spider

Reach
When Penumbra Spider dies, create a 2/4 black Spider creature token with reach.