Dr. Eggman

a Vehicle enters the battlefield — 156 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

1. Carrion Cruiser — When Carrion Cruiser enters thanks to Dr. Eggman, it mills a card

a card is discarded — 1,614 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

When a permanent makes a player discard a card thanks to Dr. Eggman:

1. Sangromancer — gains you 3 life
2. Lo and Li, Royal Advisors — puts a counter on an Advisor
3. Tourach, Dread Cantor — puts a +1/+1 counter on itself
4. Tinybones, Pocket Nuisance — deals 1 damage
5. Tinybones, Bauble Burglar — hits a graveyard
6. Fell Specter — makes each opponent lose 2 life
7. Entropic Battlecruiser — makes a player lose 3 life
8. Abyssal Nocturnus — gets +2/+2
9. Raiders' Wake — makes each opponent lose 2 life
10. Hostile Investigator — triggers

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

a card is drawn — 2,594 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

When Dr. Eggman makes a player draw a card:

1. Niv-Mizzet, Parun — deals 1 damage
2. Aether Syphon — mills a card
3. The Locust God — makes a token
4. Starving Revenant — makes each opponent lose 1 life
5. Diviner's Wand — gets +1/+1
6. Ominous Seas — puts a foreshadow counter on itself
7. Iron Man, Armored Avenger — puts a counter on a creature
8. Psychosis Crawler — makes each opponent lose 1 life
9. Lyla, Holographic Assistant — puts a counter on a creature
10. Data, New Life — puts a +1/+1 counter on itself

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

a Human enters the battlefield — 2,102 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

When Dr. Eggman enters:

1. Captain of the Mists — untaps itself
2. Erkenbrand, Lord of Westfold — gives +1/+0
3. Vigilante Justice — deals 1 damage

a card in a graveyard — 5,218 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

1. Heart-Shaped Herb — Dr. Eggman puts cards into the graveyard that Heart-Shaped Herb can bring back
2. Tergrid, God of Fright // Tergrid's Lantern — Dr. Eggman puts cards into the graveyard that Tergrid, God of Fright // Tergrid's Lantern can bring back
3. Dauthi Voidwalker — Cards Dr. Eggman would put into an opponent's graveyard are exiled by Dauthi Voidwalker instead, and it can play from among them
4. Thieves' Guild Enforcer — Dr. Eggman fills an opponent's graveyard toward the 8 or more cards Thieves' Guild Enforcer needs
5. Soaring Thought-Thief — Dr. Eggman fills an opponent's graveyard toward the 8 or more cards Soaring Thought-Thief needs
6. Picklock Prankster // Free the Fae — Dr. Eggman puts cards into the graveyard that Picklock Prankster // Free the Fae can bring back
7. Reito Sentinel — Dr. Eggman puts cards into the graveyard that Reito Sentinel can bring back
8. Szarekh, the Silent King — Dr. Eggman puts cards into the graveyard that Szarekh, the Silent King can bring back
9. Merfolk Windrobber — Dr. Eggman fills an opponent's graveyard toward the 8 or more cards Merfolk Windrobber needs
10. Relic Golem — Dr. Eggman fills an opponent's graveyard toward the 8 or more cards Relic Golem needs

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

anything goes to a graveyard — 5,218 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

When a card hits the graveyard thanks to Dr. Eggman:

1. The Haunt of Hightower — puts a +1/+1 counter on itself
2. Duskmantle Guildmage — makes each opponent lose 1 life
3. Bloodchief Ascension — makes each opponent lose 2 life
4. Planar Void — hits a graveyard

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

anything attacks — 9,608 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

When Dr. Eggman attacks:

1. Far Fortune, End Boss — deals 1 damage
2. Grim Javelineer — gives +1/+0
3. ED-E, Lonesome Eyebot — puts a quest counter on itself
4. Fire Navy Trebuchet — makes a token
5. Inti, Seneschal of the Sun — triggers
6. Cool but Rude — draws and discards
7. Gossip's Talent — triggers
8. Gut, True Soul Zealot — sacrifices a creature or artifact

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

a creature attacks — 9,608 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

When Dr. Eggman attacks:

1. Adaptive Omnitool — searches a library
2. Anthem of Rakdos — gives +2/+0
3. Kindred Discovery — draws you 1 card
4. Chorale of the Void — brings a card back
5. Saw — sacrifices a creature
6. Gisa's Favorite Shovel — makes an opponent sacrifice a creature
7. Ultima Weapon — kills a creature an opponent controls

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

a creature blocks — 9,608 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

When Dr. Eggman blocks:

1. Tide of War — sacrifices a creature
2. Dead-Iron Sledge — kills a creature

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

a creature enters the battlefield — 10,550 cards in Dr. Eggman's colors can cause this (Dr. Eggman is one).

1. Slash, Reptile Rampager — When a Construct, Robot or Vehicle enters thanks to Dr. Eggman, Slash, Reptile Rampager deals 2 damage
2. Gimli of the Glittering Caves — When Dr. Eggman enters, Gimli of the Glittering Caves puts counters on a permanent
3. Ray Fillet, Wave Warrior — When Dr. Eggman enters, Ray Fillet, Wave Warrior puts a counter on itself
4. Wingnut, Bat on the Belfry — When a Construct, Robot or Vehicle enters thanks to Dr. Eggman, Wingnut, Bat on the Belfry grants flying, haste and menace
5. Raphael, Most Attitude — When a Construct, Robot or Vehicle enters thanks to Dr. Eggman, Raphael, Most Attitude exiles a card from your library

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