Groundskeeper

put a land into a graveyard — 634 cards in the game can cause this.

1. Sequestered Stash — Sequestered Stash puts cards into the graveyard that Groundskeeper can bring back
2. Eden, Seat of the Sanctum — Eden, Seat of the Sanctum puts cards into the graveyard that Groundskeeper can bring back

632 other cards cause it too. These are the ones with the most connections.

anything leaves a graveyard — 2,503 cards in the game can cause this (Groundskeeper is one).

When a land leaves a graveyard thanks to Groundskeeper:

1. Blastoneuron — makes each opponent lose 1 life
2. Defiled Crypt // Cadaver Lab — makes a token
3. Teval, the Balanced Scale — makes a token
4. Hologram Stalker — makes a token
5. Tormod, the Desecrator — makes a token
6. Quintorius, Field Historian — makes a token
7. Garrison Excavator — makes a token
8. Amzu, Swarm's Hunger — makes a token
9. Kirol, History Buff // Pack a Punch — becomes prepared
10. Teval's Judgment — triggers

13 other cards care about it too. These are the ones with the most connections.

a Human enters the battlefield — 4,639 cards in the game can cause this (Groundskeeper is one).

When Groundskeeper enters:

1. General Kudro of Drannith — hits a graveyard
2. Heronblade Elite — puts a +1/+1 counter on itself
3. Kyler, Sigardian Emissary — puts a +1/+1 counter on itself
4. Thalia's Lieutenant — puts a +1/+1 counter on itself
5. Champion of the Parish — puts a +1/+1 counter on itself
6. Captain of the Mists — untaps itself
7. Erkenbrand, Lord of Westfold — gives +1/+0
8. Beregond of the Guard — gives +1/+1
9. Théoden, King of Rohan — grants double strike
10. Lossarnach Captain — taps a creature an opponent controls

2 other cards care about it too. These are the ones with the most connections.

anything attacks — 17,934 cards in the game can cause this (Groundskeeper is one).

When Groundskeeper attacks:

1. Far Fortune, End Boss — deals 1 damage
2. Temmet, Naktamun's Will — draws you 1 card
3. Grim Javelineer — gives +1/+0
4. Invisible Woman — triggers
5. Caesar, Legion's Emperor — sacrifices a creature
6. Guide of Souls — triggers
7. Campsite Cuisine — sacrifices a Food
8. Gossip's Talent — triggers
9. Banon, the Returners' Leader — draws and discards
10. Toph, Earthbending Master — puts a counter on a permanent

112 other cards care about it too. These are the ones with the most connections.

a creature attacks — 17,934 cards in the game can cause this (Groundskeeper is one).

When Groundskeeper attacks:

1. Adaptive Omnitool — searches a library
2. Anthem of Rakdos — gives +2/+0
3. Kindred Discovery — draws you 1 card
4. Invasion of New Capenna // Holy Frazzle-Cannon — puts counters on a permanent
5. Chorale of the Void — brings a card back
6. Anim Pakal, Thousandth Moon — puts a +1/+1 counter on itself
7. Saw — sacrifices a creature
8. Gisa's Favorite Shovel — makes an opponent sacrifice a creature
9. Ultima Weapon — kills a creature an opponent controls
10. Total War — kills a creature

181 other cards care about it too. These are the ones with the most connections.

a creature blocks — 17,934 cards in the game can cause this (Groundskeeper is one).

When Groundskeeper blocks:

1. Mage Hunters' Onslaught — makes a player lose 1 life
2. Carnage Gladiator — makes a player lose 1 life
3. Barrow-Blade — strips abilities
4. Heat of Battle — deals 1 damage
5. Battle Strain — deals 1 damage
6. Tide of War — sacrifices a creature
7. Dead-Iron Sledge — kills a creature
8. Dwindle — kills a creature
9. Shield of the Righteous — triggers

19 other cards care about it too. These are the ones with the most connections.

a nontoken creature attacks — 17,934 cards in the game can cause this (Groundskeeper is one).

When Groundskeeper attacks:

1. Mardu Ascendancy — makes a token
2. Basri Ket — makes a token
3. Militia's Pride — makes a token

a creature enters the battlefield — 19,800 cards in the game can cause this (Groundskeeper is one).

When Groundskeeper enters:

1. Slash, Reptile Rampager — deals 2 damage
2. Ray Fillet, Wave Warrior — puts a counter on itself
3. Bess, Soul Nourisher — puts a +1/+1 counter on itself
4. The Neutrinos — gets +1/+0
5. Wingnut, Bat on the Belfry — grants flying, haste and menace
6. Aetherstorm Roc — puts a counter on a permanent you control
7. Raphael, Most Attitude — exiles a card from your library

304 other cards care about it too. These are the ones with the most connections.

anything enters the battlefield — 26,499 cards in the game can cause this (Groundskeeper is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When Groundskeeper enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

42 other cards care about it too. These are the ones with the most connections.