Card

Arcane Laboratory

Mana cost {2}{U}

Each player can't cast more than one spell each turn.

Part of 4 known combos, 4 of them two-card. 3 official rulings.

Bracket

B1 Exhibition — Not in the same deck as its two-card combo partners: Knowledge Pool, Possibility Storm, Eye of the Storm, Erayo, Soratami Ascendant // Erayo's Essence
B2 Core — Not in the same deck as its two-card combo partners: Knowledge Pool, Possibility Storm, Eye of the Storm, Erayo, Soratami Ascendant // Erayo's Essence
B3 Upgraded — Not in the same deck as its early two-card combo partners: Knowledge Pool, Possibility Storm, Eye of the Storm
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Two-card combo with Knowledge Pool, Possibility Storm, Eye of the Storm, Erayo, Soratami Ascendant // Erayo's Essence (early with Knowledge Pool, Possibility Storm, Eye of the Storm)

Bracket: Lotus Vault analysis, with Commander Spellbook flags

4 known combos, 4 of them two-card.

Arcane Laboratory + Knowledge Pool
Produces: Exile all spells players cast from their hand, Players can only cast one spell per turn, Lock
View on Commander Spellbook
Possibility Storm + Arcane Laboratory
Produces: Players can't cast spells from their hand, Lock
View on Commander Spellbook
Arcane Laboratory + Eye of the Storm
Produces: Exile all instants and sorceries any player casts, Players can only cast one spell per turn, Lock
View on Commander Spellbook

2004-10-04 · Wizards of the Coast
When it leaves the battlefield, the effect ends and all players are able to cast spells unrestricted again.
2004-10-04 · Wizards of the Coast
When Arcane Laboratory enters, it will look back over the turn to see if any spell was cast before it entered the battlefield. It will notice itself being cast.
2004-10-04 · Wizards of the Coast
If a spell is countered, it still counts as the one spell cast.

Rulings: Scryfall · Wizards of the Coast