
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 has 15 printings, first in Unlimited Edition (1993). EDHREC ranks it #2,995 among Commander cards. It appears most in Lorehold, the Historian decks (8,790 on EDHREC). It has 9 official rulings.
Deck counts from EDHREC.
Cards that show up in the same decks on EDHREC.