That's because Elspeth, Storm Slayer is a token doubler masquerading as an MTG planeswalker
The mechanic was a flavorful and mechanical success
Legality depends on the tournament format -- Foundry Inspector can be legal in some formats and banned or restricted in others
Most Magic: The Gathering cards are printed at standard trading card dimensions of 2.5" x 3.5" (64mm x 89mm)
Your Side Deck can consist of between 0 to 12 of the following: Between 0 and 12 cards Between 0 and 3 Legendary Duelists with a Character Skill For example, a Side Deck could be made up of 9 cards and 3 additional Legendary Duelists with a Character Skill or 1 additional Legendary Duelist with 3 different Character Skills Any changes can be made to the Deck between Duels of a Match, including the following: Adding Cards Subtracting Cards Changing Legendary Duelist Changing Character Skill The Deck must be legal for play (appropriate number of cards in the Main and Side Deck, complies with the Forbidden and Limited list available within the DUEL LINKS app)
2023 won't be an exception: the set currently under the spotlight for tabletop Magic is Commander Masters , which is almost entirely a reprint set, and Magic Arena just got the Historic Anthology 7 , the Explorer Anthology 3 , and the return of the Explorer Anthology 2 all reprints