Is Library of Leng legal in Standard, Modern, and Commander?

Library of Leng is legal in: Legacy, Vintage, Commander, Pauper.

What type of card is Library of Leng?

Library of Leng is an Artifact. Its oracle text reads: "You have no maximum hand size.If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard."

Library of Leng

Artifact

You have no maximum hand size.<br>If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.

Set Limited Edition Alpha

Rarity Uncommon

Artist Daniel Gelon