If that Digimon has a special ability that states 'When this card makes its appearance', they are activated immediately after the card makes its appearance (the person second to attack will activate this ability first, before the person first to attack makes their Digimon appear)
However, as Luna and Leo were taken by Trudge to the controller where Devack was, she was instead transported back to the Minus World in order to free Ancient Fairy Dragon
Upon entering the battlefield, you get to have it deal damage equal to the number of lands you control to any number of creatures or planeswalkers your opponents control, so likely around 8-ish assuming you hard cast it
That takes you to the Magic Products page, which lists all the sets ever printed, in order, including their name and expansion symbol
The "Rainbow Rainforest" theme is another favorite, allowing you to blend various colors