Legacy is bit like Vintage, but with much wider ban/restriction list.
In Legacy you have following rules for creating your deck:
- Minimum 60 cards in your deck
- Maximum 15 cards in your side board
- No banned cards
read more here:
https://magic.wizards.com/en/game-info/gameplay/formats/legacy
https://mtg.gamepedia.com/Legacy
What is your favority Legacy deck?
MTG blog 