In Quantum Leap Magic you can only use cards that have the old borders, so anything that you can’t use in Modern.
more directly in sets it goes from Alpha to Odyssey.
The main difference of Ancient and QL magic is that in Ancient you play with the modern rules, and in QL magic you play with the original rules. So there is a format where you can still die from mana burn!
read more:
https://mtg.gamepedia.com/QL_Magic
What is/would be your favorite QL Magic deck?
MTG blog 