Questlines based on notable pvp events/tournaments throughout original's history. Mostly large events, though collections like "finals battles of weekly pvp tournaments in 2016" are also an option.
For each historical event we add, there would be two main branches under that quest:
(1) Play against the decks used in the event with a deck of your choice that conforms to the rules of the event.
(2) Replay the actual matches of the event in order using the actual decks.
Using war as an example:
-Questline #1 has 12 sub-branches, each consisting of one team's decks used in war. You can either play them one at a time or you can play against one randomly. You must use a deck conforming to war's broad deckbuilding rules.
-Questline #2 has 12 sub-branches, one for each team. You play through the matches that team played in order using the actual decks.
The changes in cards will mean that not every deck will be at the same performance level, but it's still likely an interesting and extensive set of battles with a wide variety of rules we can bring to quest mode.