Traditional is a deckbuilding rule modifier, much like penny dreadful. Traditional imposes the following deckbuilding restrictions:
Any card with the Planeswalker type is banned.
This includes any cards that become, spawn, transform, rotate, flip, morph or whatever new mechanics are thought of to bring another side of the card into the game.
Declaring a card as companion is banned.
Companion as a mechanic is banned in Traditional. You may still use the creature itself in your main deck or as a sideboard slot.
All cards printed exclusively in mythic rare are banned.
If it was ever printed or reprinted as a rare, it's good to go.
The following is a Modern ban list that Traditional is based on: https://scryfall.com/search?as=grid&order=name&q=banned%3Amodern
Since this is a modifier, you can pick your own base card set and then apply the Traditional restrictions.
Effectively most things you would play, with the aforementioned bans. Please refer to this list: https://scryfall.com/search?q=-r%3Amythic+-t%3Aplaneswalker&order=set&as=grid&unique=cards
2020-07-26 - Tournament #14: Ethiopian BIRRRR
2020-06-21 - Tournament #9: Scottish Pound Sterling
2020-06-14 - Unnamed Tournament #8
2020-06-06 - Tournament #7: French Frank
2020-05-30 - Tournament #6: Enter the Witness
Frequently Asked Questions
This section clarifies frequently asked questions from people getting started with the format. If your question is not listed here, the moderators in the Traditional MTG Discord server will be more than happy to answer them. Don't be afraid to ask!
Why are mythic rares banned?
WotC originally stated that mythic rares were to be assigned to cards that "felt mythic" and unlikely to become format staples, e.g., Godsire. Instead, their intentions strayed when WotC began printing staples at mythic rare even if they didn't feel epic or deserving of mythic rare in order to push packs, driving up the costs of many decks. Examples of mythic rare cards that were obviously printed as such in order to sell packs include: Lotus Cobra; Warren Instigator for Goblin decks; and Scapeshift, which was upgraded from rare by WotC.
Furthermore, Richard Garfield feels that mythic rares were a mistake.
Why not (un)ban [card]?
While we are aware that some may want certain cards from Modern to be unbanned, it would
make the format more complex than necessary and difficult to follow.
When making exceptions to cards, we run the risk of creating a kitchen table ban list and not clearly defining the Traditional format; e.g., One with Nothing is hardly powerful in Pauper, but since it was never a common, it cannot be played in Pauper due to its format's rules.
We are considering the possibility of running our own ban list after the format gains traction.
Starting with Ethiopian BIRRRR we've started experimenting with banlists and more deckbuilding rules, thanks to Eternal Witness.
Why the Planeswalker ban?
Planeswalkers are banned because they represent a design within the game that inherently generates too much immediate value, and are difficult to remove or interact with. Some Planeswalkers, like Teferi, Time Raveler and Nissa, Who Shakes the World, have effects that bounce creatures or create creatures, giving them a built-in way to protect themselves the moment they hit the battlefield, and nullifying creatures as a form of removal for them. Because they are played at sorcery speed, the player playing them will have priority after playing them, allowing them to get value out of them before the other player has a chance to respond, effectively nullifying certain forms of interaction that the other player may have for them, such as Fry and Lightning Bolt. The only efficient removal for them require black (e.g., Assassin's Trophy, The Elderspell, and Thoughtseize), meaning other colors are shafted in terms of having an effective way to deal with them. In addition, Richard Garfield himself dislikes Planeswalkers conceptually.