What is Classic Legacy?
Classic Legacy is an unofficial Magic the Gathering format, created in 2020 by Lluís Cortès, an Old School player from Barcelona. It is a tribute to what he considers to be the golden era of the official Legacy format, with Rise of the Eldrazi as the last legal expansion.
You can check out the list of legal sets here. Note that all reprints of the cards originally printed in this sets are legal, although first prints are preferred. For example, Onslaught fetch lands are preferred over Khans of Tarkir ones.
As you probably know by now, there are not restricted cards in Legacy, so if the card is legal, the you may always run the playset. Isn’t it cool? The banned cards list is here.