Is Trinisphere legal in Standard, Modern, and Commander?

Trinisphere is legal in: Modern, Legacy, Commander.

Trinisphere

Q: What type of card is Trinisphere?

Trinisphere is an Artifact. Its oracle text reads: "As long as this artifact is untapped, each spell that would cost less than three mana to cast costs three mana to cast. (Additional mana in the cost may be paid with any color of mana or colorless mana. For example, a spell that would cost {1}{B} to cast costs {2}{B} to cast instead.)"

Artifact

$20.53 ↗2 similarCommander, Modern

As long as this artifact is untapped, each spell that would cost less than three mana to cast costs three mana to cast. (Additional mana in the cost may be paid with any color of mana or colorless mana. For example, a spell that would cost to cast costs to cast instead.)